Substituted seven-membered heterocyclic compounds as dipeptidyl peptidase-iv inhibitors for the treatment of diabetes

ABSTRACT

The present invention is directed to novel amino-substituted seven-membered heterocyclic compounds of structural formula (I) which are inhibitors of the dipeptidyl peptidase-IV enzyme and which are useful in the treatment or prevention of diseases in which the dipeptidyl peptidase-IV enzyme is involved, such as diabetes and particularly Type 2 diabetes. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the prevention or treatment of such diseases in which the dipeptidyl peptidase-IV enzyme is involved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C. §371 of PCT Application No. PCT/US2011/06589, filed May 16, 2011, which published as WO 2011/146358 A1 on Nov. 24, 2011, and claims priority under 35 U.S.C. §365(b) from U.S. patent application No. 61/346,943, filed May 21, 2010.

FIELD OF THE INVENTION

The present invention relates to novel amino-substituted seven-membered heterocyclic compounds which are inhibitors of the dipeptidyl peptidase-IV enzyme (“DPP-4 inhibitors”) and which are useful in the treatment of diseases in which the dipeptidyl peptidase-IV enzyme is involved, such as diabetes and particularly Type 2 diabetes. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the treatment of such diseases in which the dipeptidyl peptidase-IV enzyme is involved.

BACKGROUND OF THE INVENTION

Diabetes refers to a disease process derived from multiple causative factors and characterized by elevated levels of plasma glucose or hyperglycemia in the fasting state or after administration of glucose during an oral glucose tolerance test. Persistent or uncontrolled hyperglycemia is associated with increased and premature morbidity and mortality. Often abnormal glucose homeostasis is associated both directly and indirectly with alterations of the lipid, lipoprotein and apolipoprotein metabolism and other metabolic and hemodynamic disease. Therefore patients with Type 2 diabetes mellitus are at especially increased risk of macrovascular and microvascular complications, including coronary heart disease, stroke, peripheral vascular disease, hypertension, nephropathy, neuropathy, and retinopathy. Therefore, therapeutical control of glucose homeostasis, lipid metabolism and hypertension are critically important in the clinical management and treatment of diabetes mellitus.

There are two generally recognized forms of diabetes. In Type 1 diabetes, or insulin-dependent diabetes mellitus (IDDM), patients produce little or no insulin, the hormone which regulates glucose utilization. In Type 2 diabetes, or noninsulin dependent diabetes mellitus (NIDDM), patients often have plasma insulin levels that are the same or even elevated compared to nondiabetic subjects; however, these patients have developed a resistance to the insulin stimulating effect on glucose and lipid metabolism in the main insulin-sensitive tissues, which are muscle, liver and adipose tissues, and the plasma insulin levels, while elevated, are insufficient to overcome the pronounced insulin resistance.

Insulin resistance is not primarily due to a diminished number of insulin receptors but to a post-insulin receptor binding defect that is not yet understood. This resistance to insulin responsiveness results in insufficient insulin activation of glucose uptake, oxidation and storage in muscle and inadequate insulin repression of lipolysis in adipose tissue and of glucose production and secretion in the liver.

The available treatments for Type 2 diabetes, which have not changed substantially in many years, have recognized limitations. While physical exercise and reductions in dietary intake of calories will dramatically improve the diabetic condition, compliance with this treatment is very poor because of well-entrenched sedentary lifestyles and excess food consumption, especially of foods containing high amounts of saturated fat. Increasing the plasma level of insulin by administration of sulfonylureas (e.g. tolbutamide and glipizide) or meglitinide, which stimulate the pancreatic β cells to secrete more insulin, and/or by injection of insulin when sulfonylureas or meglitinide become ineffective, can result in insulin concentrations high enough to stimulate the very insulin-resistant tissues. However, dangerously low levels of plasma glucose can result from administration of insulin or insulin secretagogues (sulfonylureas or meglitinide), and an increased level of insulin resistance due to the even higher plasma insulin levels can occur. The biguanides increase insulin sensitivity resulting in some correction of hyperglycemia. However, the two biguanides, phenformin and metformin, can induce lactic acidosis and nausea/diarrhea. Metformin has fewer side effects than phenformin and is often prescribed for the treatment of Type 2 diabetes.

The glitazones (i.e. 5-benzylthiazolidine-2,4-diones) constitute an additional class of compounds with potential for ameliorating many symptoms of Type 2 diabetes. These agents substantially increase insulin sensitivity in muscle, liver and adipose tissue in several animal models of Type 2 diabetes resulting in partial or complete correction of the elevated plasma levels of glucose without occurrence of hypoglycemia. The glitazones that are currently marketed are agonists of the peroxisome proliferator activated receptor (PPAR), primarily the PPAR-gamma subtype. PPAR-gamma agonism is generally believed to be responsible for the improved insulin sensititization that is observed with the glitazones. Newer PPAR agonists that are being tested for treatment of Type 2 diabetes are agonists of the alpha, gamma or delta subtype, or a combination of these, and in many cases are chemically different from the glitazones (i.e., they are not thiazolidinediones in structure). Serious side effects (e.g. liver toxicity) have occurred with some of the glitazones, such as troglitazone.

Additional methods of treating the disease are still under investigation. New biochemical approaches that have been recently introduced or are still under development include alpha-glucosidase inhibitors (e.g. acarbose), GLP-1 mimetics (eg., exenatide and liraglutide), glucagon receptor antagonists, glucokinase activators, and GPR-119 agonists.

Compounds that are inhibitors of the dipeptidyl peptidase-IV (“DPP-4”) enzyme have also been found useful for the treatment of diabetes, particularly Type 2 diabetes [See WO 97/40832; WO 98/19998; U.S. Pat. No. 5,939,560; U.S. Pat. No. 6,303,661; U.S. Pat. No. 6,699,871; U.S. Pat. No. 6,166,063; Bioorg. Med. Chem. Lett., 6: 1163-1166 (1996); Bioorg. Med. Chem. Lett., 6: 2745-2748 (1996); D. J. Drucker in Exp. Opin. Invest. Drugs, 12: 87-100 (2003); K. Augustyns, et al., Exp. Opin. Ther. Patents, 13: 499-510 (2003); Ann E. Weber, J. Med. Chem., 47: 4135-4141 (2004); J. J. Hoist, Exp. Opin. Emerg. Drugs, 9: 155-166 (2004); D. Kim, et al., J. Med. Chem., 48: 141-151 (2005); K. Augustyns, Exp. Opin. Ther. Patents, 15: 1387-1407 (2005); H.-U. Demuth in Biochim. Biophys. Acta, 1751: 33-44 (2005); and R. Mentlein, Exp. Opin. Invest. Drugs, 14: 57-64 (2005).

Additional patent publications that disclose DPP-4 inhibitors useful for the treatment of diabetes are the following: WO 2006/009886 (26 Jan. 2006); WO 2006/039325 (13 Apr. 2006); WO 2006/058064 (1 Jun. 2006); WO 2006/127530 (30 Nov. 2006); WO 2007/024993 (1 Mar. 2007); WO 2007/070434 (21 Jun. 2007); WO 2007/087231 (2 Aug. 2007); WO 07/097931 (30 Aug. 2007); WO 07/126745 (8 Nov. 2007); WO 07/136603 (29 Nov., 2007); and WO 08/060488 (22 May 2008).

The usefulness of DPP-4 inhibitors in the treatment of Type 2 diabetes is based on the fact that DPP-4 in vivo readily inactivates glucagon like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP). GLP-1 and GIP are incretins and are produced when food is consumed. The incretins stimulate production of insulin. Inhibition of DPP-4 leads to decreased inactivation of the incretins, and this in turn results in increased effectiveness of the incretins in stimulating production of insulin by the pancreas. DPP-4 inhibition therefore results in an increased level of serum insulin. Advantageously, since the incretins are produced by the body only when food is consumed, DPP-4 inhibition is not expected to increase the level of insulin at inappropriate times, such as between meals, which can lead to excessively low blood sugar (hypoglycemia). Inhibition of DPP-4 is therefore expected to increase insulin without increasing the risk of hypoglycemia, which is a dangerous side effect associated with the use of insulin secretagogues.

DPP-4 inhibitors also have other therapeutic utilities, as discussed herein. New compounds are needed so that improved DPP-4 inhibitors can be found for the treatment of diabetes and potentially other diseases and conditions. In particular, there is a need for DPP-4 inhibitors that are selective over other members of the family of serine peptidases that includes quiescent cell proline dipeptidase (QPP), DPP8, and DPP9 [see G. Lankas, et al., “Dipeptidyl Peptidase-IV Inhibition for the Treatment of Type 2 Diabetes: Potential Importance of Selectivity Over Dipeptidyl Peptidases 8 and 9,” Diabetes, 54: 2988-2994 (2005); N. S. Kang, et al., “Docking-based 3D-QSAR study for selectivity of DPP4, DPP8, and DPP9 inhibitors,” Bioorg. Med. Chem. Lett., 17: 3716-3721 (2007)].

The therapeutic potential of DPP-4 inhibitors for the treatment of Type 2 diabetes is discussed by (i) D. J. Drucker, Exp. Opin. Invest. Drugs, 12: 87-100 (2003); (ii) K. Augustyns, et al., Exp. Opin. Ther. Patents, 13: 499-510 (2003); (iii) J. J. Hoist, Exp. Opin. Emerg. Drugs, 9: 155-166 (2004); (iv) H.-U. Demuth, et al., Biochim. Biophys. Acta, 1751: 33-44 (2005); (v) R. Mentlein, Exp. Opin. Invest. Drugs, 14: 57-64 (2005); (vi) K. Augustyns, “Inhibitors of proline-specific dipeptidyl peptidases: DPP IV inhibitors as a novel approach for the treatment of Type 2 diabetes,” Exp. Opin. Ther. Patents, 15: 1387-1407 (2005); (vii) D. J. Drucker and M. A. Nauck, “The incretin system: GLP-1 receptor agonists and dipeptidyl peptidase-4 inhibitors in Type 2 diabetes,” The Lancet, 368: 1696-1705 (2006); (viii) T. W. von Geldern and J. M. Trevillyan, ““The Next Big Thing” in Diabetes: Clinical Progress on DPP-IV Inhibitors,” Drug Dev. Res., 67: 627-642 (2006); (ix) B. D. Green et al., “Inhibition of dipeptidyl peptidase IV activity as a therapy of Type 2 diabetes,” Exp. Opin. Emerging Drugs, 11: 525-539 (2006); (x) J. J. Hoist and C. F. Deacon, “New Horizons in Diabetes Therapy,” Immun., Endoc. & Metab. Agents in Med. Chem., 7: 49-55 (2007); (xi) R. K. Campbell, “Rationale for Dipeptidyl Peptidase 4 Inhibitors: a New Class of Oral Agents for the Treatment of Type 2 Diabetes Mellitus,” Ann. Pharmacother., 41: 51-60 (2007); (xii) Z. Pei, “From the bench to the bedside: Dipeptidyl peptidase IV inhibitors, a new class of oral antihyperglycemic agents,” Curr. Opin. Drug Discovery Development, 11: 512-532 (2008); and (xiii) J. J. Hoist, et al., “Glucagon-like peptide-1, glucose homeostasis, and diabetes, Trends in Molecular Medicine, 14: 161-168 (2008). Specific DPP-4 inhibitors either already approved or under clinical investigation for the treatment of Type 2 diabetes include sitagliptin, vildagliptin, saxagliptin, alogliptin, carrnegliptin, melogliptin, and dutogliptin.

SUMMARY OF THE INVENTION

The present invention is directed to novel amino-substituted seven-membered heterocyclic compounds which are inhibitors of the dipeptidyl peptidase-IV enzyme (“DPP-4 inhibitors”) and which are useful in the treatment of diseases in which the dipeptidyl peptidase-IV enzyme is involved, such as diabetes and particularly Type 2 diabetes. The invention is also directed to pharmaceutical compositions comprising these compounds and the use of these compounds and compositions in the treatment of such diseases in which the dipeptidyl peptidase-IV enzyme is involved.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to novel amino-substituted seven-membered heterocyclic compounds that are useful as inhibitors of dipeptidyl peptidase-IV. Compounds of the present invention are described by structural formula I:

and pharmaceutically acceptable salts thereof; wherein

-   X is O or S; -   V is selected from the group consisting of:

-   Ar is phenyl optionally substituted with one to five R¹     substituents; -   each R¹ is independently selected from the group consisting of     -   halogen,     -   cyano,     -   hydroxy,     -   C₁₋₆ alkyl, optionally substituted with one to five fluorines,         and     -   C₁₋₆ alkoxy, optionally substituted with one to five fluorines; -   each R² is independently selected from the group consisting of     -   hydrogen,     -   hydroxy,     -   halogen,     -   cyano,     -   heteroaryl,     -   C₁₋₁₀ alkoxy, wherein alkoxy is optionally substituted with one         to five substituents independently selected from fluorine and         hydroxy,     -   C₁₋₁₀ alkyl, wherein alkyl is optionally substituted with one to         five substituents independently selected from fluorine and         hydroxy,     -   C₂₋₁₀ alkenyl, wherein alkenyl is optionally substituted with         one to five substituents independently selected from fluorine         and hydroxy,     -   (CH₂)-aryl, wherein aryl is optionally substituted with one to         five substituents independently selected hydroxy, halogen,         cyano, nitro, CO₂H, C₁₋₆ alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆         alkoxy, wherein alkyl and alkoxy are optionally substituted with         one to five fluorines,     -   (CH₂)-heteroaryl, wherein heteroaryl is optionally substituted         with one to three substituents independently selected from         hydroxy, halogen, cyano, nitro, CO₂H, C₁₋₆ alkyloxycarbonyl,         C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are         optionally substituted with one to five fluorines,     -   (CH₂)-heterocyclyl, wherein heterocyclyl is optionally         substituted with one to three substituents independently         selected from oxo, hydroxy, halogen, cyano, nitro, CO₂H, C₁₋₆         alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and         alkoxy are optionally substituted with one to five fluorines,     -   (CH₂)—C₃₋₆ cycloalkyl, wherein cycloalkyl is optionally         substituted with one to three substituents independently         selected from halogen, hydroxy, cyano, nitro, CO₂H, C₁₋₆         alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and         alkoxy are optionally substituted with one to five fluorines,     -   (CH₂)—COOH,     -   (CH₂)—COOC₁₋₆ alkyl,     -   (CH₂)—NR⁴R⁵,     -   (CH₂)—CONR⁴R⁵,     -   (CH₂)—OCONR⁴R⁵,     -   (CH₂)—SO₂NR⁴R⁵,     -   (CH₂)—SO₂R⁶,     -   (CH₂)—NR⁷SO₂R⁶,     -   (CH₂)—NR⁷CONR⁴R⁵,     -   (CH₂)—NR⁷COR⁷, and     -   (CH₂)—NR⁷CO₂R⁶; -   wherein any individual methylene (CH₂) carbon atom is optionally     substituted with one to two substituents independently selected from     fluorine, hydroxy, C₁₋₄ alkyl, and C₁₋₄ alkoxy, wherein alkyl and     alkoxy are optionally substituted with one to five fluorines; -   R^(3a), R^(3b) and R^(3c) are each independently hydrogen or C₁₋₄     alkyl optionally substituted with one to five fluorines; -   R⁴ and R⁵ are each independently selected from the group consisting     of     -   hydrogen,     -   (CH₂)-phenyl,     -   (CH₂)—C₃₋₆ cycloalkyl, and     -   C₁₋₆ alkyl, wherein alkyl is optionally substituted with one to         five substituents independently selected from fluorine and         hydroxy and wherein phenyl and cycloalkyl are optionally         substituted with one to five substituents independently selected         from halogen, hydroxy, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein         alkyl and alkoxy are optionally substituted with one to five         fluorines; -   or R⁴ and R⁵ together with the nitrogen atom to which they are     attached form a heterocyclic ring selected from azetidine,     pyrrolidine, piperidine, piperazine, and morpholine wherein said     heterocyclic ring is optionally substituted with one to three     substituents independently selected from halogen, hydroxy, C₁₋₆     alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally     substituted with one to five fluorines; -   each R⁶ is independently C₁₋₆ alkyl, wherein alkyl is optionally     substituted with one to five substituents independently selected     from fluorine and hydroxyl; -   R⁷ is hydrogen or R⁶; and -   R⁸ is selected from the group consisting of     -   -hydrogen,     -   —(CH₂)-phenyl,     -   —(CH₂)-heteroaryl,     -   —(CH₂)—C₃₋₆ cycloalkyl,     -   —SO₂C₁₋₆ alkyl,     -   —CH₂SO₂C₁₋₆ alkyl,     -   —SO₂C₃₋₆ cycloalkyl, and     -   —C₁₋₆ alkyl, wherein each alkyl residue is optionally         substituted with one to five substituents independently selected         from fluorine and hydroxy and wherein phenyl, heteroaryl, and         each cycloalkyl residue are optionally substituted with one to         five substituents independently selected from halogen, hydroxy,         C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are         optionally substituted with one to five fluorines.

In one embodiment of the compounds of the present invention, Ar is optionally substituted with one to three substituents independently selected from the group consisting of fluorine, chlorine, bromine, methyl, trifluoromethyl, and trifluoromethoxy. In a class of this embodiment, Ar is 2,5-difluorophenyl or 2,4,5-trifluorophenyl.

In a second embodiment of the compounds of the present invention, R^(3a), R^(3b) and R^(3c) are each hydrogen.

In a third embodiment of the compounds of the present invention, there are provided compounds of structural formulae Ia and Ib of the indicated stereochemical configuration having a trans orientation of the Ar and NH₂ substituents on the two stereogenic carbon atoms marked with an *:

wherein X, Ar, and V are as defined above.

In a class of this third embodiment, there are provided compounds of structural formula Ia of the indicated absolute stereochemical configuration having a trans orientation of the Ar and NH₂ substituents on the two stereogenic carbon atoms marked with an *:

In a second class of this third embodiment, there are provided compounds of structural formulae Ic and Id of the indicated stereochemical configuration having a trans orientation of the Ar and NH₂ substituents, a trans orientation of the Ar and V substituents and a cis orientation of the NH₂ and V substituents on the three stereogenic carbon atoms marked with an*:

In a subclass of this class, there are provided compounds of structural formula Ic of the indicated absolute stereochemical configuration having a trans orientation of the Ar and NH₂ substituents, a trans orientation of the Ar and V substituents and a cis orientation of the NH₂ and V substituents on the three stereogenic carbon atoms marked with an *:

In a subclass of this subclass, V is selected from the group consisting of

wherein R² and R⁸ are as defined above.

In a second subclass of this subclass, V is selected from the group consisting of:

wherein R² and R⁸ are as defined above.

In a fourth embodiment of the compounds of the present invention, R^(3a), R^(3b) and R^(3c) are each hydrogen, and R² is selected from the group consisting of

-   -   hydrogen;     -   cyano;     -   CONH₂;     -   C₁₋₃ alkyl, wherein alkyl is optionally substituted with one to         five fluorines; and     -   C₃₋₅ cycloalkyl, wherein cycloalkyl is optionally substituted         with one to three substituents independently selected from         halogen, hydroxy, and C₁₋₄ alkyl, wherein alkyl is optionally         substituted with one to five fluorines.

In a fifth embodiment of the compounds of the present invention, R^(3a), R^(3b) and R^(3c) are each hydrogen, and R⁸ is selected from the group consisting of

-   -   -hydrogen;     -   -phenyl;     -   -heteroaryl;     -   —C₃₋₆ cycloalkyl;     -   —SO₂C₁₋₃ alkyl;     -   —CH₂SO₂C₁₋₃ alkyl;     -   —SO₂C₃₋₆ cycloalkyl; and     -   —C₁₋₅ alkyl; wherein each alkyl residue is optionally         substituted with one to five substituents independently selected         from fluorine and hydroxy and wherein phenyl, heteroaryl, and         each cycloalkyl residue are optionally substituted with one to         five substituents independently selected from halogen, hydroxy,         C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are         optionally substituted with one to five fluorines.

In a sixth embodiment of the compounds of the present invention, V is selected from the group consisting of:

wherein R² and R⁸ are as defined above.

In a class of this embodiment, V is selected from the group consisting of:

wherein R² and R⁸ are as defined above.

In a subclass of this class, R² is selected from the group consisting of:

-   -   hydrogen;     -   cyano;     -   CONH₂;     -   C₁₋₃ alkyl, wherein alkyl is optionally substituted with one to         five fluorines; and     -   C₃₋₅ cycloalkyl, wherein eycloalkyl is optionally substituted         with one to three substituents independently selected from         halogen, hydroxy, and C₁₋₄ alkyl, wherein alkyl is optionally         substituted with one to five fluorines; and         R⁸ is selected from the group consisting of:     -   -hydrogen;     -   -phenyl;     -   -heteroaryl;     -   —C₃₋₆ cycloalkyl;     -   —SO₂C₁₋₃ alkyl;     -   —CH₂SO₂C₁₋₃ alkyl;     -   —SO₂C₃₋₆ cycloalkyl; and     -   —C₁₋₅ alkyl; wherein each alkyl residue is optionally         substituted with one to five substituents independently selected         from fluorine and hydroxy and wherein phenyl, heteroaryl, and         each cycloalkyl residue are optionally substituted with one to         five substituents independently selected from halogen, hydroxy,         C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are         optionally substituted with one to five fluorines.

Nonlimiting examples of compounds of the present invention that are useful as dipeptidyl peptidase-IV inhibitors are the following structures having the indicated absolute stereochemical configurations at the three stereogenic carbon atoms with their DPP-4 inhibition constants:

IC₅₀ DPP-4 Inhi- Example bition

2.3 nM

2.2 nM

3.0 nM

8.5 nM

2.6 nM

5.8 nM

0.5 nM

4.0 nM

4.1 nM

14.3  nM

21.1  nM

5.9 nM

8.1 nM

12.6  nM

As used herein the following definitions are applicable.

“Alkyl”, as well as other groups having the prefix “alk”, such as alkoxy and alkanoyl, means carbon chains which may be linear or branched, and combinations thereof, unless the carbon chain is defined otherwise. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec- and tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, and the like. Where the specified number of carbon atoms permits, e.g., from C₃₋₁₀, the term alkyl also includes cycloalkyl groups, and combinations of linear or branched alkyl chains combined with cycloalkyl structures. When no number of carbon atoms is specified, C₁₋₆ is intended.

“Cycloalkyl” is a subset of alkyl and means a saturated carbocyclic ring having a specified number of carbon atoms. Examples of cycloalkyl include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. A cycloalkyl group generally is monocyclic unless stated otherwise. Cycloalkyl groups are saturated unless otherwise defined.

The term “alkoxy” refers to straight or branched chain alkoxides of the number of carbon atoms specified (e.g., C₁₋₁₀ alkoxy), or any number within this range [i.e., methoxy (MeO—), ethoxy, isopropoxy, etc.].

The term “alkylthio” refers to straight or branched chain alkylsulfides of the number of carbon atoms specified (e.g., C₁₋₁₀ alkylthio), or any number within this range [i.e., methylthio (MeS—), ethylthio, isopropylthio, etc.].

The term “alkylamino” refers to straight or branched alkylamines of the number of carbon atoms specified (e.g., C₁₋₆ alkylamino), or any number within this range [i.e., methylamino, ethylamino, isopropylamino, t-butylamino, etc.].

The term “alkylsulfonyl” refers to straight or branched chain alkylsulfones of the number of carbon atoms specified (e.g., C₁₋₆ alkylsulfonyl), or any number within this range [i.e., methylsulfonyl (MeSO₂—), ethylsulfonyl, isopropylsulfonyl, etc.].

The term “alkyloxycarbonyl” refers to straight or branched chain esters of a carboxylic acid derivative of the present invention of the number of carbon atoms specified (e.g., C₁₋₆ alkyloxycarbonyl), or any number within this range [i.e., methyloxycarbonyl (MeOCO—), ethyloxycarbonyl, or butyloxycarbonyl].

“Aryl” means a mono- or polycyclic aromatic ring system containing carbon ring atoms. The preferred aryls are monocyclic or bicyclic 6-10 membered aromatic ring systems. Phenyl and naphthyl are preferred aryls. Naphthyl can be either 1-naphthyl or 2-naphthyl. The most preferred aryl is phenyl.

The term “heterocyclyl” refers to saturated or unsaturated non-aromatic rings or ring systems containing at least one heteroatom selected from O, S and N, further including the oxidized forms of sulfur, namely SO and SO₂. Examples of heterocycles include tetrahydrofuran (THF), dihydrofuran, 1,4-dioxane, morpholine, 1,4-dithiane, piperazine, piperidine, 1,3-dioxolane, imidazolidine, imidazoline, pyrroline, pyrrolidine, tetrahydropyran, dihydropyran, oxathiolane, dithiolane, 1,3-dioxane, 1,3-dithiane, oxathiane, thiomorpholine, pyrrolidinone, oxazolidin-2-one, imidazolidine-2-one, pyridone, and the like.

“Heteroaryl” means an aromatic or partially aromatic heterocycle that contains at least one ring heteroatom selected from O, S and N. Heteroaryls also include heteroaryls fused to other kinds of rings, such as aryls, cycloalkyls and heterocycles that are not aromatic. Examples of heteroaryl groups include pyrrolyl, isoxazolyl, isothiazolyl, pyrazolyl, pyridinyl, 2-oxo-(1H)-pyridinyl(2-hydroxy-pyridinyl), oxazolyl, 1,2,4-oxadiazolyl, 1,3,4-oxadiazolyl, thiadiazolyl, thiazolyl, imidazolyl, triazolyl, tetrazolyl, furyl, triazinyl, thienyl, pyrimidinyl, pyrazinyl, benzisoxazolyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, dihydrobenzofuranyl, indolinyl, pyridazinyl, indazolyl, isoindolyl, dihydrobenzothienyl, indolizinyl, cinnolinyl, phthalazinyl, quinazolinyl, naphthyridinyl, carbazolyl, benzodioxolyl, quinoxalinyl, purinyl, furazanyl, isobenzylfuranyl, benzimidazolyl, benzofuranyl, benzothienyl, quinolyl, indolyl, isoquinolyl, dibenzofuranyl, imidazo[1,2-a]pyridinyl, [1,2,4-triazolo][4,3-a]pyridinyl, pyrazolo[1,5-a]pyridinyl, [1,2,4-triazolo][1,5-a]pyridinyl, 2-oxo-1,3-benzoxazolyl, 4-oxo-3H-quinazolinyl, 3-oxo-[1,2,4]-triazolo[4,3-a]-2H-pyridinyl, 5-oxo-[1,2,4]-4H-oxadiazolyl, 2-oxo-[1,3,4]-3H-oxadiazolyl, 2-oxo-1,3-dihydro-2H-imidazolyl, 3-oxo-2,4-dihydro-3H-1,2,4-triazolyl, and the like. For heterocyclyl and heteroaryl groups, rings and ring systems containing from 3-15 atoms are included, forming 1-3 rings.

“Halogen” refers to fluorine, chlorine, bromine and iodine. Chlorine and fluorine are generally preferred. Fluorine is most preferred when the halogens are substituted on an alkyl or alkoxy group (e.g. CF₃O and CF₃CH₂O).

The compounds of the present invention contain one or more asymmetric centers and can thus occur as racemates, racemic mixtures, single enantiomers, diastereomeric mixtures, and individual diastereomers. In particular the compounds of the present invention have an asymmetric center at the stereogenic carbon atoms marked with an * in formulae Ia, Ib, Ic, and Id. Additional asymmetric centers may be present depending upon the nature of the various substituents on the molecule. Each such asymmetric center will independently produce two optical isomers and it is intended that all of the possible optical isomers and diastereomers in mixtures and as pure or partially purified compounds are included within the ambit of this invention. The present invention is meant to comprehend all such isomeric forms of these compounds.

Some of the compounds described herein contain olefinic double bonds, and unless specified otherwise, are meant to include both E and Z geometric isomers.

Some of the compounds described herein may exist as tautomers, which have different points of attachment of hydrogen accompanied by one or more double bond shifts. For example, a ketone and its enol form are keto-enol tautomers. The individual tautomers as well as mixtures thereof are encompassed with compounds of the present invention. An example of tautomers which are intended to be encompassed within the compounds of the present invention is illustrated below:

Formula I shows the structure of the class of compounds without preferred stereochemistry. Formulae Ia and Ib show the preferred stereochemistry at the stereogenic carbon atoms to which are attached the NH₂ and Ar groups on the seven-membered heterocyclic ring. Formulae Ic and Id show the preferred stereochemistry at the stereogenic carbon atoms to which are attached the NH₂, Ar, and V groups on the seven-membered heterocyclic ring.

The independent syntheses of these diastereomers or their chromatographic separations may be achieved as known in the art by appropriate modification of the methodology disclosed herein. Their absolute stereochemistry may be determined by the X-ray crystallography of crystalline products or crystalline intermediates which are derivatized, if necessary, with a reagent containing an asymmetric center of known absolute configuration.

If desired, racemic mixtures of the compounds may be separated so that the individual enantiomers are isolated. The separation can be carried out by methods well known in the art, such as the coupling of a racemic mixture of compounds to an enantiomerically pure compound to form a diastereomeric mixture, followed by separation of the individual diastereomers by standard methods, such as fractional crystallization or chromatography. The coupling reaction is often the formation of salts using an enantiomerically pure acid or base. The diasteromeric derivatives may then be converted to the pure enantiomers by cleavage of the added chiral residue. The racemic mixture of the compounds can also be separated directly by chromatographic methods utilizing chiral stationary phases, which methods are well known in the art.

Alternatively, any enantiomer of a compound may be obtained by stereoselective synthesis using optically pure starting materials or reagents of known configuration by methods well known in the art.

In the compounds of generic Formula I, the atoms may exhibit their natural isotopic abundances, or one or more of the atoms may be artificially enriched in a particular isotope having the same atomic number, but an atomic mass or mass number different from the atomic mass or mass number predominantly found in nature. The present invention is meant to include all suitable isotopic variations of the compounds of generic Formula I. For example, different isotopic forms of hydrogen (H) include protium (¹H) and deuterium (²H). Protium is the predominant hydrogen isotope found in nature. Enriching for deuterium may afford certain therapeutic advantages, such as increasing in vivo half-life or reducing dosage requirements, or may provide a compound useful as a standard for characterization of biological samples. Isotopically-enriched compounds within generic Formula I can be prepared without undue experimentation by conventional techniques well known to those skilled in the art or by processes analogous to those described in the Schemes and Examples herein using appropriate isotopically-enriched reagents and/or intermediates.

It will be understood that, as used herein, references to the compounds of structural formula I are meant to also include the pharmaceutically acceptable salts, and also salts that are not pharmaceutically acceptable when they are used as precursors to the free compounds or their pharmaceutically acceptable salts or in other synthetic manipulations.

The compounds of the present invention may be administered in the form of a pharmaceutically acceptable salt. The term “pharmaceutically acceptable salt” refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids including inorganic or organic bases and inorganic or organic acids. Salts of basic compounds encompassed within the term “pharmaceutically acceptable salt” refer to non-toxic salts of the compounds of this invention which are generally prepared by reacting the free base with a suitable organic or inorganic acid. Representative salts of basic compounds of the present invention include, but are not limited to, acetate, benzenesulfonate, benzoate, bicarbonate, bisulfate, bitartrate, borate, bromide, camsylate, carbonate, clavulanate, citrate, edetate, edisylate, estolate, esylate, fumarate, gluceptate, gluconate, glutamate, hexylresorcinate, hydrabamine, hydrobromide, hydrochloride, hydroxynaphthoate, iodide, isothionate, lactate, lactobionate, laurate, malate, maleate, mandelate, mesylate, methylbromide, methylsulfate, mucate, napsylate, nitrate, N-methylglucamine ammonium salt, oleate, oxalate, pamoate (embonate), palmitate, pantothenate, phosphate, polygalacturonate, salicylate, stearate, sulfate, subacetate, succinate, tannate, tartrate, teoclate, tosylate, triethiodide and valerate. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof include, but are not limited to, salts derived from inorganic bases including aluminum, ammonium, calcium, copper, ferric, ferrous, lithium, magnesium, manganic, mangamous, potassium, sodium, zinc, and the like. Particularly preferred are the ammonium, calcium, magnesium, potassium, and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, cyclic amines, and basic ion-exchange resins, such as arginine, betaine, caffeine, choline, N,N-dibenzylethylenediamine, diethylamine, 2-diethylaminoethanol, 2-dimethylaminoethanol, ethanolamine, ethylenediamine, N-ethylmorpholine, N-ethylpiperidine, glucamine, glucosamine, histidine, hydrabamine, isopropylamine, lysine, methylglucamine, morpholine, piperazine, piperidine, polyamine resins, procaine, purines, theobromine, triethylamine, trimethylamine, tripropylamine, tromethamine, and the like.

Also, in the case of a carboxylic acid (—COOH) or alcohol group being present in the compounds of the present invention, pharmaceutically acceptable esters of carboxylic acid derivatives, such as methyl, ethyl, or pivaloyloxymethyl, or acyl derivatives of alcohols, such as O-acetyl, O-pivaloyl, O-benzoyl, and O-aminoacyl, can be employed. Included are those esters and acyl groups known in the art for modifying the solubility or hydrolysis characteristics for use as sustained-release or prodrug formulations.

Solvates, and in particular, the hydrates of the compounds of structural formula I are included in the present invention as well.

Exemplifying the invention is the use of the compounds disclosed in the Examples and herein.

The subject compounds are useful in a method of inhibiting the dipeptidyl peptidase-IV enzyme in a patient such as a mammal in need of such inhibition comprising the administration of an effective amount of the compound. The present invention is directed to the use of the compounds disclosed herein as inhibitors of dipeptidyl peptidase-IV enzyme activity.

In addition to primates, such as humans, a variety of other mammals can be treated according to the method of the present invention. For instance, mammals including, but not limited to, cows, sheep, goats, horses, dogs, cats, guinea pigs, rats or other bovine, ovine, equine, canine, feline, rodent or murine species can be treated. However, the method can also be practiced in other species, such as avian species (e.g., chickens).

The present invention is further directed to a method for the manufacture of a medicament for inhibiting dipeptidyl peptidase-IV enzyme activity in humans and animals comprising combining a compound of the present invention with a pharmaceutically acceptable carrier or diluent. More particularly, the present invention is directed to the use of a compound of structural formula I in the manufacture of a medicament for use in treating a condition selected from the group consisting of hyperglycemia, Type 2 diabetes, obesity, and a lipid disorder in a mammal, wherein the lipid disorder is selected from the group consisting of dyslipidemia, hyperlipidemia, hypertriglyceridemia, hypercholesterolemia, low HDL, and high LDL.

The subject treated in the present methods is generally a mammal, preferably a human being, male or female, in whom inhibition of dipeptidyl peptidase-IV enzyme activity is desired. The term “therapeutically effective amount” means the amount of the subject compound that will elicit the biological or medical response of a tissue, system, animal or human that is being sought by the researcher, veterinarian, medical doctor or other clinician.

The term “composition” as used herein is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts. Such term in relation to pharmaceutical composition, is intended to encompass a product comprising the active ingredient(s), and the inert ingredient(s) that make up the carrier, as well as any product which results, directly or indirectly, from combination, complexation or aggregation of any two or more of the ingredients, or from dissociation of one or more of the ingredients, or from other types of reactions or interactions of one or more of the ingredients. Accordingly, the pharmaceutical compositions of the present invention encompass any composition made by admixing a compound of the present invention and a pharmaceutically acceptable carrier. By “pharmaceutically acceptable” it is meant the carrier, diluent or excipient must be compatible with the other ingredients of the formulation and not deleterious to the recipient thereof.

The terms “administration of” and or “administering a” compound should be understood to mean providing a compound of the invention or a prodrug of a compound of the invention to the individual in need of treatment.

The utility of the compounds in accordance with the present invention as inhibitors of dipeptidyl peptidase-IV enzyme activity may be demonstrated by methodology known in the art. Inhibition constants are determined as follows. A continuous fluorometric assay is employed with the substrate Gly-Pro-AMC, which is cleaved by DPP-4 to release the fluorescent AMC leaving group. The kinetic parameters that describe this reaction are as follows: K_(m)=50 μM; k_(cat)=75 s⁻¹; k_(cat)/K_(m)=1.5×10⁶ M⁻¹s⁻¹. A typical reaction contains approximately 50 pM enzyme, 50 μM Gly-Pro-AMC, and buffer (100 mM HEPES, pH 7.5, 0.1 mg/ml BSA) in a total reaction volume of 100 μL. Liberation of AMC is monitored continuously in a 96-well plate fluorometer using an excitation wavelength of 360 nm and an emission wavelength of 460 nm. Under these conditions, approximately 0.8 μM AMC is produced in 30 minutes at 25 degrees C. The enzyme used in these studies was soluble (transmembrane domain and cytoplasmic extension excluded) human protein produced in a baculovirus expression system (Bac-To-Bac, Gibco BRL). The kinetic constants for hydrolysis of Gly-Pro-AMC and GLP-1 were found to be in accord with literature values for the native enzyme. To measure the dissociation constants for compounds, solutions of inhibitor in DMSO were added to reactions containing enzyme and substrate (final DMSO concentration is 1%). All experiments were conducted at room temperature using the standard reaction conditions described above. To determine the dissociation constants (K_(i)), reaction rates were fit by non-linear regression to the Michaelis-Menton equation for competitive inhibition. The errors in reproducing the dissociation constants are typically less than two-fold.

The compounds of structural formula (I), particularly the specific Examples shown below, had activity in inhibiting the dipeptidyl peptidase-IV enzyme in the aforementioned assays, generally with an IC50 of less than about 1 μM, and more typically of less than 0.1 μM. Such results are indicative of the intrinsic activity of the compounds of the present invention for use as inhibitors the dipeptidyl peptidase-IV enzyme activity.

Dipeptidyl peptidase-IV enzyme (DPP-4) is a cell surface protein that has been implicated in a wide range of biological functions. It has a broad tissue distribution (intestine, kidney, liver, pancreas, placenta, thymus, spleen, epithelial cells, vascular endothelium, lymphoid and myeloid cells, serum), and distinct tissue and cell-type expression levels. DPP-4 is identical to the T cell activation marker CD26, and it can cleave a number of immunoregulatory, endocrine, and neurological peptides in vitro. This has suggested a potential role for this peptidase in a variety of disease processes in humans or other species.

Accordingly, the subject compounds are useful in a method for the prevention or treatment of the following diseases, disorders and conditions.

-   Type II Diabetes and Related Disorders: It is well established that     the incretins GLP-1 and GIP are rapidly inactivated in vivo by     DPP-4. Studies with DPP-4^((−/−))-deficient mice and preliminary     clinical trials indicate that DPP-4 inhibition increases the steady     state concentrations of GLP-1 and GIP, resulting in improved glucose     tolerance. By analogy to GLP-1 and GIP, it is likely that other     glucagon family peptides involved in glucose regulation are also     inactivated by DPP-4 (eg. PACAP). Inactivation of these peptides by     DPP-4 may also play a role in glucose homeostasis. The DPP-4     inhibitors of the present invention therefore have utility in the     treatment of type II diabetes and in the treatment and prevention of     the numerous conditions that often accompany Type II diabetes,     including Syndrome X (also known as Metabolic Syndrome), reactive     hypoglycemia, and diabetic dyslipidemia. Obesity, discussed below,     is another condition that is often found with Type II diabetes that     may respond to treatment with the compounds of this invention.

The following diseases, disorders and conditions are related to Type 2 diabetes, and therefore may be treated, controlled or in some cases prevented, by treatment with the compounds of this invention: (1) hyperglycemia, (2) low glucose tolerance, (3) insulin resistance, (4) obesity, (5) lipid disorders, (6) dyslipidemia, (7) hyperlipidemia, (8) hypertriglyceridemia, (9) hypercholesterolemia, (10) low HDL levels, (11) high LDL levels, (12) atherosclerosis and its sequelae, (13) vascular restenosis, (14) irritable bowel syndrome, (15) inflammatory bowel disease, including Crohn's disease and ulcerative colitis, (16) other inflammatory conditions, (17) pancreatitis, (18) abdominal obesity, (19) neurodegenerative disease, (20) retinopathy, (21) nephropathy, (22) neuropathy, (23) Syndrome X, (24) ovarian hyperandrogenism (polycystic ovarian syndrome), and other disorders where insulin resistance is a component. In Syndrome X, also known as Metabolic Syndrome, obesity is thought to promote insulin resistance, diabetes, dyslipidemia, hypertension, and increased cardiovascular risk. Therefore, DPP-4 inhibitors may also be useful to treat hypertension associated with this condition.

-   Obesity: DPP-4 inhibitors may be useful for the treatment of     obesity. This is based on the observed inhibitory effects on food     intake and gastric emptying of GLP-1 and GLP-2. Exogenous     administration of GLP-1 in humans significantly decreases food     intake and slows gastric emptying (Am. Physiol., 277: R910-R916     (1999)). ICY administration of GLP-1 in rats and mice also has     profound effects on food intake (Nature Medicine, 2: 1254-1258     (1996)). This inhibition of feeding is not observed in     GLP-1R^((−/−)) mice, indicating that these effects are mediated     through brain GLP-1 receptors. By analogy to GLP-1, it is likely     that GLP-2 is also regulated by DPP-4. ICY administration of GLP-2     also inhibits food intake, analogous to the effects observed with     GLP-1 (Nature Medicine, 6: 802-807 (2000)). In addition, studies     with DPP-4 deficient mice suggest that these animals are resistant     to diet-induced obesity and associated pathology (e.g.     hyperinsulinonemia). -   Cardiovascular Disease: GLP-1 has been shown to be beneficial when     administered to patients following acute myocardial infarction,     leading to improved left ventricular function and reduced mortality     after primary angioplasty (Circulation, 109: 962-965 (2004)). GLP-1     administration is also useful for the treatment of left ventricular     systolic dysfunction in dogs with dilated cardiomyopathy and     ischemic induced left ventricular dysfunction, and thus may prove     useful for the treatment of patients with heart failure     (US2004/0097411). DPP-4 inhibitors are expected to show similar     effects through their ability to stabilize endogenous GLP-1. -   Growth Hormone Deficiency: DPP-4 inhibition may be useful for the     treatment of growth hormone deficiency, based on the hypothesis that     growth-hormone releasing factor (GRF), a peptide that stimulates     release of growth hormone from the anterior pituitary, is cleaved by     the DPP-4 enzyme in vivo (WO 00/56297). The following data provide     evidence that GRF is an endogenous substrate: (1) GRF is efficiently     cleaved in vitro to generate the inactive product GRF[3-44] (BBA     1122: 147-153 (1992)); (2) GRF is rapidly degraded in plasma to     GRF[3-44]; this is prevented by the DPP-4 inhibitor diprotin A;     and (3) GRF[3-44] is found in the plasma of a human GRF transgenic     pig (J. Clin. Invest., 83: 1533-1540 (1989)). Thus DPP-4 inhibitors     may be useful for the same spectrum of indications which have been     considered for growth hormone secretagogues. -   Intestinal Injury: The potential for using DPP-4 inhibitors for the     treatment of intestinal injury is suggested by the results of     studies indicating that glucagon-like peptide-2 (GLP-2), a likely     endogenous substrate for DPP-4, may exhibit trophic effects on the     intestinal epithelium (Regulatory Peptides, 90: 27-32 (2000)).     Administration of GLP-2 results in increased small bowel mass in     rodents and attenuates intestinal injury in rodent models of colitis     and enteritis. -   Immunosuppression: DPP-4 inhibition may be useful for modulation of     the immune response, based upon studies implicating the DPP-4 enzyme     in T cell activation and in chemokine processing, and efficacy of     DPP-4 inhibitors in in vivo models of disease. DPP-4 has been shown     to be identical to CD26, a cell surface marker for activated immune     cells. The expression of CD26 is regulated by the differentiation     and activation status of immune cells. It is generally accepted that     CD26 functions as a co-stimulatory molecule in in vitro models of T     cell activation. A number of chemokines contain proline in the     penultimate position, presumably to protect them from degradation by     non-specific aminopeptidases. Many of these have been shown to be     processed in vitro by DPP-4. In several cases (RANTES, LD78-beta,     MDC, eotaxin, SDF-1alpha), cleavage results in an altered activity     in chemotaxis and signaling assays. Receptor selectivity also     appears to be modified in some cases (RANTES). Multiple N-terminally     truncated forms of a number of chemokines have been identified in in     vitro cell culture systems, including the predicted products of     DPP-4 hydrolysis.

DPP-4 inhibitors have been shown to be efficacious immunosuppressants in animal models of transplantation and arthritis. Prodipine (Pro-Pro-diphenyl-phosphonate), an irreversible inhibitor of DPP-4, was shown to double cardiac allograft survival in rats from day 7 to day 14 (Transplantation, 63: 1495-1500 (1997)). DPP-4 inhibitors have been tested in collagen and alkyldiamine-induced arthritis in rats and showed a statistically significant attenuation of hind paw swelling in this model [Int. J. Immunopharmacology, 19:15-24 (1997) and Immunopharmacology, 40: 21-26 (1998)]. DPP-4 is upregulated in a number of autoimmune diseases including rheumatoid arthritis, multiple sclerosis, Graves' disease, and Hashimoto's thyroiditis (Immunology Today, 20: 367-375 (1999)).

-   HIV Infection: DPP-4 inhibition may be useful for the treatment or     prevention of HIV infection or AIDS because a number of chemokines     which inhibit HIV cell entry are potential substrates for DPP-4     (Immunology Today 20: 367-375 (1999)). In the case of SDF-1alpha,     cleavage decreases antiviral activity (PNAS, 95: 6331-6 (1998)).     Thus, stabilization of SDF-1alpha through inhibition of DPP-4 would     be expected to decrease HIV infectivity. -   Hematopoiesis: DPP-4 inhibition may be useful for the treatment or     prevention of hematopiesis because DPP-4 may be involved in     hematopoiesis. A DPP-4 inhibitor, Val-Boro-Pro, stimulated     hematopoiesis in a mouse model of cyclophosphamide-induced     neutropenia (WO 99/56753). -   Neuronal Disorders: DPP-4 inhibition may be useful for the treatment     or prevention of various neuronal or psychiatric disorders because a     number of peptides implicated in a variety of neuronal processes are     cleaved in vitro by DPP-4. A DPP-4 inhibitor thus may have a     therapeutic benefit in the treatment of neuronal disorders.     Endomorphin-2, beta-casomorphin, and substance P have all been shown     to be in vitro substrates for DPP-4. In all cases, in vitro cleavage     is highly efficient, with k_(cat)/K_(m) about 10⁶ M⁻¹ s⁻¹ or     greater. In an electric shock jump test model of analgesia in rats,     a DPP-4 inhibitor showed a significant effect that was independent     of the presence of exogenous endomorphin-2 (Brain Research, 815:     278-286 (1999)). Neuroprotective and neuroregenerative effects of     DPP-4 inhibitors were also evidenced by the inhibitors' ability to     protect motor neurons from excitotoxic cell death, to protect     striatal innervation of dopaminergic neurons when administered     concurrently with MPTP, and to promote recovery of striatal     innervation density when given in a therapeutic manner following     MPTP treatment [see Yong-Q. Wu, et al., “Neuroprotective Effects of     Inhibitors of Dipeptidyl peptidase-IV In Vitro and In Vivo,” Int.     Conf. On Dipeptidyl Aminopeptidases: Basic Science and Clinical     Applications, Sep. 26-29, 2002 (Berlin, Germany)]. -   Anxiety: Rats naturally deficient in DPP-4 have an anxiolytic     phenotype (WO 02/34243; Karl et al., Physiol. Behay. 2003). DPP-4     deficient mice also have an anxiolytic phenotype using the porsolt     and light/dark models. Thus DPP-4 inhibitors may prove useful for     treating anxiety and related disorders. -   Memory and Cognition: GLP-1 agonists are active in models of     learning (passive avoidance, Morris water maze) and neuronal injury     (kainate-induced neuronal apoptosis) as demonstrated by During et     al. (Nature Med. 9: 1173-1179 (2003)). The results suggest a     physiological role for GLP-1 in learning and neuroprotection.     Stabilization of GLP-1 by DPP-4 inhibitors are expected to show     similar effects -   Myocardial Infarction: GLP-1 has been shown to be beneficial when     administered to patients following acute myocardial infarction     (Circulation, 109: 962-965 (2004)). DPP-4 inhibitors are expected to     show similar effects through their ability to stabilize endogenous     GLP-1. -   Tumor Invasion and Metastasis: DPP-4 inhibition may be useful for     the treatment or prevention of tumor invasion and metastasis because     an increase or decrease in expression of several ectopeptidases     including DPP-4 has been observed during the transformation of     normal cells to a malignant phenotype (J. Exp. Med., 190: 301-305     (1999)). Up- or down-regulation of these proteins appears to be     tissue and cell-type specific. For example, increased CD26/DPP-4     expression has been observed on T cell lymphoma, T cell acute     lymphoblastic leukemia, cell-derived thyroid carcinomas, basal cell     carcinomas, and breast carcinomas. Thus, DPP-4 inhibitors may have     utility in the treatment of such carcinomas. -   Benign Prostatic Hypertrophy: DPP-4 inhibition may be useful for the     treatment of benign prostatic hypertrophy because increased DPP-4     activity was noted in prostate tissue from patients with BPH     (Eur. J. Clin. Chem. Clin. Biochem., 30: 333-338 (1992)). -   Sperm motility/male contraception: DPP-4 inhibition may be useful     for the altering sperm motility and for male contraception because     in seminal fluid, prostatosomes, prostate derived organelles     important for sperm motility, possess very high levels of DPP-4     activity (Eur. J. Clin. Chem. Clin. Biochem., 30: 333-338 (1992)). -   Gingivitis: DPP-4 inhibition may be useful for the treatment of     gingivitis because DPP-4 activity was found in gingival crevicular     fluid and in some studies correlated with periodontal disease     severity (Arch. Oral Biol., 37: 167-173 (1992)). -   Osteoporosis: DPP-4 inhibition may be useful for the treatment or     prevention of osteoporosis because GIP receptors are present in     osteoblasts. -   Stem Cell Transplantation: Inhibition of DPP-4 on donor stem cells     has been shown to lead to an enhancement of their bone marrow homing     efficiency and engraftment, and an increase in survival in mice     (Christopherson, et al., Science, 305:1000-1003 (2004)). Thus DPP-4     inhibitors may be useful in bone marrow transplantation.

The compounds of the present invention have utility in treating or preventing one or more of the following conditions or diseases: (1) hyperglycemia, (2) low glucose tolerance, (3) insulin resistance, (4) obesity, (5) lipid disorders, (6) dyslipidemia, (7) hyperlipidemia, (8) hypertriglyceridemia, (9) hypercholesterolemia, (10) low HDL levels, (11) high LDL levels, (12) atherosclerosis and its sequelae, (13) vascular restenosis, (14) irritable bowel syndrome, (15) inflammatory bowel disease, including Crohn's disease and ulcerative colitis, (16) other inflammatory conditions, (17) pancreatitis, (18) abdominal obesity, (19) neurodegenerative disease, (20) retinopathy, (21) nephropathy, (22) neuropathy, (23) Syndrome X, (24) ovarian hyperandrogenism (polycystic ovarian syndrome), (25) Type 2 diabetes, (26) growth hormone deficiency, (27) neutropenia, (28) neuronal disorders, (29) tumor metastasis, (30) benign prostatic hypertrophy, (32) gingivitis, (33) hypertension, (34) osteoporosis, (35) anxiety, (36) memory deficit, (37) cognition deficit, (38) stroke, (39) Alzheimer's disease, and other conditions that may be treated or prevented by inhibition of DPP-4.

The compounds of the present invention are further useful in methods for the prevention or treatment of the aforementioned diseases, disorders and conditions in combination with other therapeutic agents.

The compounds of the present invention may be used in combination with one or more other drugs in the treatment, prevention, suppression or amelioration of diseases or conditions for which compounds of Formula I or the other drugs may have utility, where the combination of the drugs together are safer or more effective than either drug alone. Such other drug(s) may be administered, by a route and in an amount commonly used therefor, contemporaneously or sequentially with a compound of Formula I. When a compound of Formula I is used contemporaneously with one or more other drugs, a pharmaceutical composition in unit dosage form containing such other drugs and the compound of Formula I is preferred, particularly in combination with a pharmaceutically acceptable carrier. However, the combination therapy may also include therapies in which the compound of Formula I and one or more other drugs are administered on different overlapping schedules. It is also contemplated that when used in combination with one or more other active ingredients, the compounds of the present invention and the other active ingredients may be used in lower doses than when each is used singly. Accordingly, the pharmaceutical compositions of the present invention include those that contain one or more other active ingredients, in addition to a compound of Formula I.

When a compound of the present invention is used contemporaneously with one or more other drugs, a pharmaceutical composition containing such other drugs in addition to the compound of the present invention is preferred. Accordingly, the pharmaceutical compositions of the present invention include those that also contain one or more other active ingredients, in addition to a compound of the present invention.

The weight ratio of the compound of the present invention to the second active ingredient may be varied and will depend upon the effective dose of each ingredient. Generally, an effective dose of each will be used. Thus, for example, when a compound of the present invention is combined with another agent, the weight ratio of the compound of the present invention to the other agent will generally range from about 1000:1 to about 1:1000, preferably about 200:1 to about 1:200. Combinations of a compound of the present invention and other active ingredients will generally also be within the aforementioned range, but in each case, an effective dose of each active ingredient should be used.

In such combinations the compound of the present invention and other active agents may be administered separately or in conjunction. In addition, the administration of one element may be prior to, concurrent to, or subsequent to the administration of other agent(s).

Examples of other active ingredients that may be administered in combination with a compound of Formula I, and either administered separately or in the same pharmaceutical composition, include, but are not limited to:

(1) insulin sensitizers, including (i) PPARγ agonists, such as the glitazones (e.g. pioglitazone, rosiglitazone, netoglitazone, rivoglitazone, and balaglitazone) and other PPAR ligands, including (1) PPARα/γ dual agonists, such as muraglitazar, aleglitazar, sodelglitazar, and naveglitazar, (2) PPARγ agonists, such as fenofibric acid derivatives (gemfibrozil, clofibrate, ciprofibrate, fenofibrate and bezafibrate), (3) selective PPARγ modulators (SPPARγM's), such as those disclosed in WO 02/060388, WO 02/08188, WO 2004/019869, WO 2004/020409, WO 2004/020408, and WO 2004/066963, and (4) PPARγ partial agonists; (ii) biguanides, such as metformin and its pharmaceutically acceptable salts, in particular, metformin hydrochloride, and extended-release formulations thereof, such as Glumetza®, Fortamet®, and GlucophageXR®; (iii) protein tyrosine phosphatase-1B (PTP-1B) inhibitors;

(2) insulin and insulin analogs or derivatives, such as insulin lispro, insulin detemir, insulin glargine, insulin glulisine, and inhalable formulations of each thereof;

(3) leptin and leptin derivatives, agonists, and analogs, such as metreleptin;

(4) amylin; amylin analogs, such as davalintide; and amylin agonists, such as pramlintide;

(5) sulfonylurea and non-sulfonylurea insulin secretagogues, such as tolbutamide, glyburide, glipizide, glimepiride, mitiglinide, and meglitinides, such as nateglinide and repaglinide;

(6) α-glucosidase inhibitors (such as acarbose, voglibose and miglitol);

(7) glucagon receptor antagonists, such as those disclosed in WO 98/04528, WO 99/01423, WO 00/39088, and WO 00/69810;

(8) incretin mimetics, such as GLP-1, GLP-1 analogs, derivatives, and mimetics (See for example, WO 2008/011446, U.S. Pat. No. 5,545,618, U.S. Pat. No. 6,191,102, and U.S. Pat. No. 5,658,3111); and GLP-1 receptor agonists, such as oxyntomodulin and its analogs and derivatives (See for example, WO 2003/022304, WO 2006/134340, WO 2007/100535), glucagon and its analogs and derivatives (See for example, WO 2008/101017), exenatide, liraglutide, taspoglutide, albiglutide, AVE0010, CJC-1134-PC, NN9535, LY2189265, LY2428757, and B1M-51077, including intranasal, transdermal, and once-weekly formulations thereof, such as exenatide QW;

(9) LDL cholesterol lowering agents such as (i) C (lovastatin, simvastatin, pravastatin, cerivastatin, fluvastatin, atorvastatin, pitavastatin, and rosuvastatin), (ii) bile acid sequestering agents (such as cholestyramine, colestimide, colesevelam hydrochloride, colestipol, and dialkylaminoalkyl derivatives of a cross-linked dextran, (iii) inhibitors of cholesterol absorption, such as ezetimibe, and (iv) acyl CoA:cholesterol acyltransferase inhibitors, such as avasimibe;

(10) HDL-raising drugs, such as niacin or a salt thereof and extended-release versions thereof; MK-524A, which is a combination of niacin extended-release and the DP-1 antagonist MK-524; and nicotinic acid receptor agonists;

(11) antiobesity compounds;

(12) agents intended for use in inflammatory conditions, such as aspirin, non-steroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, and selective cyclooxygenase-2 (COX-2) inhibitors;

(13) antihypertensive agents, such as ACE inhibitors (such as enalapril, lisinopril, ramipril, captopril, quinapril, and tandolapril), A-II receptor blockers (such as losartan, candesartan, irbesartan, olmesartan medoxomil, valsartan, telmisartan, and eprosartan), renin inhibitors (such as aliskiren), beta blockers (such as and calcium channel blockers (such as;

(14) glucokinase activators (GKAs), such as LY2599506;

(15) inhibitors of 11β-hydroxysteroid dehydrogenase type 1, such as those disclosed in U.S. Pat. No. 6,730,690; WO 03/104207; and WO 04/058741;

(16) inhibitors of cholesteryl ester transfer protein (CETP), such as torcetrapib and MK-0859;

(17) inhibitors of fructose 1,6-bisphosphatase, such as those disclosed in U.S. Pat. Nos. 6,054,587; 6,110,903; 6,284,748; 6,399,782; and 6,489,476;

(18) inhibitors of acetyl CoA carboxylase-1 or 2 (ACC1 or ACC2);

(19) AMP-activated Protein Kinase (AMPK) activators;

(20) agonists of the G-protein-coupled receptors: GPR-109, GPR-116, GFR-119, and GPR-40;

(21) SSTR3 antagonists, such as those disclosed in WO 2009/011836;

(22) neuromedin U receptor 1 (NMUR1) and/or neuromedin U receptor 2 (NMUR2) agonists, such as those disclosed in WO2007/109135 and WO2009/042053, including, but not limited to, neuromedin U (NMU) and neuromedin S (NMS) and their analogs and derivatives;

(23) inhibitors of stearoyl-coenzyme A delta-9 desaturase (SCD);

(24) GPR-105 (P2YR14) antagonists, such as those disclosed in WO 2009/000087;

(25) inhibitors of glucose uptake, such as sodium-glucose transporter (SGLT) inhibitors and its various isoforms, such as SGLT-1; SGLT-2, such as dapagliflozin and remogliflozin; and SGLT-3;

(26) inhibitors of acyl coenzyme A:diacylglycerol acyltransferase 1 and 2 (DGAT-1 and DGAT-2);

(27) inhibitors of fatty acid synthase;

(28) inhibitors of acyl coenzyme A:monoacylglycerol acyltransferase 1 and 2 (MGAT-1 and MGAT-2);

(29) agonists of the TGR5 receptor (also known as GPBAR1, BG37, GPCR19, GPR131, and M-BAR);

(30) bromocriptine mesylate and rapid-release formulations thereof.;

(31) histamine H3 receptor agonists; and

(32) α2-adrenergic or β3-adrenergic receptor agonists.

Antiobesity compounds that can be combined with compounds of Formula I include topiramate; zonisamide; naltrexone; phentermine; bupropion; the combination of bupropion and naltrexone; the combination of bupropion and zonisamide; the combination of topiramate and phentermine; fenfluramine; dexfenfluramine; sibutramine; lipase inhibitors, such as orlistat and cetilistat; melanocortin receptor agonists, in particular, melanocortin-4 receptor agonists; CCK-1 agonists; melanin-concentrating hormone (MCH) receptor antagonists; neuropeptide Y₁ or Y₅ antagonists (such as MK-0557); CB1 receptor inverse agonists and antagonists (such as rimonabant and taranabant); β₃ adrenergic receptor agonists; ghrelin antagonists; bombesin receptor agonists (such as bombesin receptor subtype-3 agonists); histamine H3 receptor inverse agonists; 5-hydroxytryptamine-2c (5-HT2c) agonists, such as lorcaserin; and inhibitors of fatty acid synthase (FAS). For a review of anti-obesity compounds that can be combined with compounds of the present invention, see S. Chaki et al., “Recent advances in feeding suppressing agents: potential therapeutic strategy for the treatment of obesity,” Expert Opin. Ther. Patents, 11: 1677-1692 (2001); D. Spanswick and K. Lee, “Emerging antiobesity drugs,” Expert Opin. Emerging Drugs, 8: 217-237 (2003); J. A. Fernandez-Lopez, et al., “Pharmacological Approaches for the Treatment of Obesity,” Drugs, 62: 915-944 (2002); and K. M. Gadde, et al., “Combination pharmaceutical therapies for obesity,” Exp. Opin. Pharmacother., 10: 921-925 (2009).

Glucagon receptor antagonists that can be used in combination with the compounds of Formula I include, but are not limited to:

-   N-[4-((1S)-1-{3-(3,5-dichlorophenyl)-5-[6-(trifluoromethoxy)-2-naphthyl]-1H-pyrazol-1-yl}ethyl)benzoyl]-β-alanine; -   N-[4-((1R)-1-{3-(3,5-dichlorophenyl)-5-[6-(trifluoromethoxy)-2-naphthyl]-1H-pyrazol-1-yl}ethyl)benzoyl]-β-alanine; -   N-(4-{1-[3-(2,5-dichlorophenyl)-5-(6-methoxy-2-naphthyl)-1H-pyrazol-1-yl]ethyl}benzoyl)-β-alanine; -   N-(4-{(1S)-1-[3-(3,5-dichlorophenyl)-5-(6-methoxy-2-naphthyl)-1H-pyrazol-1-yl]ethyl}benzoyl)-β-alanine; -   N-(4-{(1S)-1-[(R)-(4-chlorophenyl)(7-fluoro-5-methyl-1H-indol-3-yl)methyl]butyl}benzoyl)-β-alanine;     and -   N-(4-{(1S)-1-[(4-chlorophenyl)(6-chloro-8-methylquinolin-4-yl)methyl]butyl}benzoyl)-β-alanine;     and -   pharmaceutically acceptable salts thereof.

Inhibitors of stearoyl-coenzyme A delta-9 desaturase (SCD) that can be used in combination with the compounds of Formula I include, but are not limited to:

-   [5-(5-{4-[2-(trifluoromethyl)phenoxy]piperidin-1-yl}-1,3,4-thiadiazol-2-yl)-2H-tetrazol-2-yl]acetic     acid; -   (2′-{4-[2-(trifluoromethyl)phenoxy]piperidin-1-yl}-2,5′-bi-1,3-thiazol-4-yl)acetic     acid; -   (5-{3-[4-(2-bromo-5-fluorophenoxy)piperidin-1-yl]isoxazol-5-yl}-2H-tetrazol-2-yl)acetic     acid; -   (3-{3-[4-(2-bromo-5-fluorophenoxy)piperidin-1-yl]-1,2,4-oxadiazol-5-yl}-1H-pyrrol-1-yl)acetic     acid; -   (5-{5-[4-(2-bromo-5-fluorophenoxy)piperidin-1-yl]pyrazin-2-yl}-2H-tetrazol-2-yl)acetic     acid; and -   (5-{2-[4-(5-bromo-2-chlorophenoxy)piperidin-1-yl]pyrimidin-5-yl}-2H-tetrazol-2-yl)acetic     acid; and -   pharmaceutically acceptable salts thereof.

Glucokinase activators that can be used in combination with the compounds of Formula I include, but are not limited to:

-   3-(6-ethanesulfonylpyridin-3-yloxy)-5-(2-hydroxy-1-methyl-ethoxy)-N-(1-methyl-1H-pyrazol-3-yl)benzamide; -   5-(2-hydroxy-1-methyl-ethoxy)-3-(6-methanesulfonylpyridin-3-yloxy)-N-(1-methyl-1H-pyrazol-3-yl)benzamide; -   5-(1-hydroxymethyl-propoxy)-3-(6-methanesulfonylpyridin-3-yloxy)-N-(1-methyl-1H-pyrazol-3-yl)benzamide; -   3-(6-methanesulfonylpyridin-3-yloxy)-5-(1-methoxymethyl-propoxy)-N-(1-methyl-1H-pyrazol-3-yl)benzamide; -   5-isopropoxy-3-(6-methanesulfonylpyridin-3-yloxy)-N-(1-methyl-1H-pyrazol-3-yl)benzamide; -   5-(2-fluoro-1-fluoromethyl-ethoxy)-3-(6-methanesulfonylpyridin-3-yloxy)-N-(1-methyl-1H-pyrazol-3-yl)benzamide; -   3-({4-[2-(dimethylamino)ethoxy]phenyl}thio)-N-(3-methyl-1,2,4-thiadiazol-5-yl)-6-[(4-methyl-4H-1,2,4-triazol-3-yl)thio]pyridine-2-carboxamide; -   3-({4-[(1-methylazetidin-3-yl)oxy]phenyl}thio)-N-(3-methyl-1,2,4-thiadiazol-5-yl)-6-[(4-methyl-4H-1,2,4-triazol-3-yl)thio]pyridine-2-carboxamide; -   N-(3-methyl-1,2,4-thiadiazol-5-yl)-6-[(4-methyl-4H-1,2,4-triazol-3-yl)thio]-3-{[4-(2-pyrrolidin-1-ylethoxy)phenyl]thio}pyridine-2-carboxamide;     and -   3-[(4-{2-[(2R)-2-methylpyrrolidin-1-yl]ethoxy}phenyl)thio-N-(3-methyl-1,2,4-thiadiazol-5-yl)-6-[(4-methyl-4H-1,2,4-triazol-3-yl)thio]pyridine-2-carboxamide;     and pharmaceutically acceptable salts thereof.

Agonists of the GPR-119 receptor that can be used in combination with the compounds of Formula I include, but are not limited to:

-   rac-cis     5-chloro-2-{4-[2-(2-{[5-(methylsulfonyl)pyridin-2-yl]oxy}ethyl)cyclopropyl]piperidin-1-yl}pyrimidine; -   5-chloro-2-{4-[(1R,2S)-2-(2-{[5-(methylsulfonyl)pyridin-2-yl]oxy}ethypcyclopropyl]piperidin-1-yl}pyrimidine; -   rac     cis-5-chloro-2-[4-(2-{2-[4-(methylsulfonyl)phenoxy]ethyl}cyclopropyl)piperidin-1-yl]pyrimidine; -   5-chloro-2-[4-((1S,2R)-2-{2-[4-(methylsulfonyl)phenoxy]ethyl}cyclopropyl)piperidin-1-yl]pyrimidine; -   5-chloro-2-[4-((1R,2S)-2-{2-[4-(methylsulfonyl)phenoxy]ethyl}cyclopropyl)piperidin-1-yl]pyrimidine; -   rac     cis-5-chloro-2-[4-(2-{2-[3-(methylsulfonyl)phenoxy]ethyl}cyclopropyl)piperidin-1-yl]pyrimidine;     and -   rac     cis-5-chloro-2-[4-(2-{2-[3-(5-methyl-1,3,4-oxadiazol-2-yl)phenoxy]ethyl}cyclopropyl)piperidin-1-yl]pyrimidine;     and -   pharmaceutically acceptable salts thereof.

Selective PPARγ modulators (SPPARγM's) that can be used in combination with the compounds of Formula I include, but are not limited to:

-   (2S)-2-({6-chloro-3-[6-(4-chlorophenoxy)-2-propylpyridin-3-yl]-1,2-benzisoxazol-5-yl}oxy)propanoic     acid; -   (2S)-2-({6-chloro-3-[6-(4-fluorophenoxy)-2-propylpyridin-3-yl]-1,2-benzisoxazol-5-yl}oxy)propanoic     acid; -   (2S)-2-{[6-chloro-3-(6-phenoxy-2-propylpyridin-3-yl)-1,2-benzisoxazol-5-yl]oxy}propanoic     acid; -   (2R)-2-({6-chloro-3-[6-(4-chlorophenoxy)-2-propylpyridin-3-yl]-1,2-benzisoxazol-5-yl}oxy)propanoic     acid; -   (2R)-2-{3-[3-(4-methoxy)benzoyl-2-methyl-6-(trifluoromethoxy)-1H-indol-1-yl]phenoxy}butanoic     acid; -   (2S)-2-{3-[3-(4-methoxy)benzoyl-2-methyl-6-(trifluoromethoxy)-1H-indol-1-yl]phenoxy}butanoic     acid; -   2-{3-[3-(4-methoxy)benzoyl-2-methyl-6-(trifluoromethoxy)-1H-indol-1-yl]phenoxy}-2-methylpropanoic     acid; and -   (2R)-2-{3-[3-(4-chloro)benzoyl-2-methyl-6-(trifluoromethoxy)-1H-indol-1-yl]phenoxy}propanoic     acid; and -   pharmaceutically acceptable salts thereof.

Inhibitors of 11β-hydroxysteroid dehydrogenase type 1 that can be used in combination with the compounds of Formula I include, but are not limited to:

-   3-[1-(4-chlorophenyl)-trans-3-fluorocyclobutyl]-4,5-dicyclopropyl-r-4H-1,2,4-triazole; -   3-[1-(4-chlorophenyl)-trans-3-fluorocyclobutyl]-4-cyclopropyl-5-(1-methylcyclopropyl)-r-4H-1,2,4-triazole; -   3-[1-(4-chlorophenyl)-trans-3-fluorocyclobutyl]-4-methyl-5-[2-(trifluoromethoxy)phenyl]-r-4H-1,2,4-triazole; -   3-[1-(4-chlorophenyl)cyclobutyl]-4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazole; -   3-{4-[3-(ethylsulfonyl)propyl]bicyclo[2.2.2]oct-1-yl}-4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazole; -   4-methyl-3-{4-[4-(methylsulfonyl)phenyl]bicyclo[2.2.2]oct-1-yl}-5-[2-(trifluaromethyl)phenyl]-4H-1,2,4-triazole; -   3-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]act-1-yl)-5-(3,3,3-trifluoropropyl)-1,2,4-oxadiazole; -   3-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]oct-1-yl)-5-(3,3,3-trifluoroethyl)-1,2,4-oxadiazole; -   5-(3,3-difluorocyclobutyl)-3-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]oct-1-yl)-1,2,4-oxadiazole; -   5-(1-fluoro-1-methylethyl)-3-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]oct-1-yl)-1,2,4-oxadiazole; -   2-(1,1-difluoroethyl)-5-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]oct-1-yl)-1,3,4-axadiazole; -   2-(3,3-difluorocyclobutyl)-5-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]oct-1-yl)-1,3,4-oxadiazole;     and -   5-(1,1-difluoroethyl)-3-(4-{4-methyl-5-[2-(trifluoromethyl)phenyl]-4H-1,2,4-triazol-3-yl}bicyclo[2.2.2]act-1-yl)-1,2,4-oxadiazole;     and -   pharmaceutically acceptable salts thereof.

Somatostatin subtype receptor 3 (SSTR3) antagonists that can be used in combination with the compounds of Formula I include, but are not limited to:

and pharmaceutically acceptable salts thereof.

AMP-activated Protein Kinase (AMPK) activators that can be used in combination with the compounds of Formula I include, but are not limited to:

and pharmaceutically acceptable salts thereof.

Inhibitors of acetyl-CoA carboxylase-1 and 2 (ACC-1 and ACC-2) that can be used in combination with the compounds of Formula I include, but are not limited to:

-   3-{1′-[(1-cyclopropyl-4-methoxy-1H-indol-6-yl)carbonyl]-4-oxospiro[chroman-2,4′-piperidin]-6-yl}benzoic     acid; -   5-{1′-[(1-cyclopropyl-4-methoxy-1H-indol-6-yl)carbonyl]-4-oxospiro[chroman-2,4′-piperidin]-6-yl}nicotinic     acid; -   1′-[(1-cyclopropyl-4-methoxy-1H-indol-6-yl)carbonyl]-6-(1H-tetrazol-5-yl)spiro[chroman-2,4′-piperidin]-4-one; -   1′-[(1-cyclopropyl-4-ethoxy-3-methyl-1H-indol-6-yl)carbonyl]-6-(1H-tetrazol-5-yl)spiro[chroman-2,4′-piperidin]-4-one; -   5-{1′-[(1-cyclopropyl-4-methoxy-3-methyl-1H-indol-6-yl)carbonyl]-4-oxo-spiro[chroman-2,4′-piperidin]-6-yl}nicotinic     acid; -   4′-({6-(5-carbamoylpyridin-2-yl)-4-oxospiro[chroman-2,4′-piperidin]-1′-yl}carbonyl)-2′,6-diethoxybiphenyl-4-carboxylic     acid; -   2′,6′-diethoxy-4′-{[6-(1-methyl-1H-pyrazol-4-yl)-4-oxospiro[chroman-2,4′-piperidin]-1′-yl]carbonyl}biphenyl-4-carboxylic     acid; -   2′,6′-diethoxy-3-fluoro-4′-{[6-(1-methyl-1H-pyrazol-4-yl)-4-oxospiro[chroman-2,4′-piperidin]-1′-yl]carbonyl}biphenyl-4-carboxylic     acid; -   5-[4-({6-(3-carbamoylphenyl)-4-oxospiro[chroman-2,4′-piperidin]-1′-yl}carbonyl)-2,6-diethoxyphenyl]nicotinic     acid; -   sodium     4′-({6-(5-carbamoylpyridin-2-yl)-4-oxospiro[chroman-2,4′-piperidin]-1′-yl}carbonyl)-2′,6′-diethoxybiphenyl-4-carboxylate; -   methyl     4′-({6-(5-carbamoylpyridin-2-yl)-4-oxospiro[chroman-2,4′-piperidin]-1′-yl}carbonyl)-2′,6′-diethoxybiphenyl-4-carboxylate; -   1′-[(4,8-dimethoxyquinolin-2-yl)carbonyl]-6-(1H-tetrazol-5-yl)spiro[chroman-2,4′-piperidin]-4-one; -   (5-{1′-[(4,8-dimethoxyquinolin-2-yl)carbonyl]-4-oxospiro[chroman-2,4′-piperidin]-6-yl}-2H-tetrazol-2-yl)methyl     pivalate; -   5-{1′-[(8-cyclopropyl-4-methoxyquinolin-2-yl)carbonyl]-4-oxospiro[chroman-2,4′-piperidin]-6-yl}nicotinic     acid; -   1′-(8-methoxy-4-morpholin-4-yl-2-naphthoyl)-6-(1H-tetrazol-5-yl)spiro[chroman-2,4′-piperidin]-4-one;     and -   1′-[(4-ethoxy-8-ethylquinolin-2-yl)carbonyl]-6-(1H-tetrazol-5-yl)spiro[chroman-2,4′-piperidin]-4-one;     and -   pharmaceutically acceptable salts and esters thereof.

The compounds of the present invention may be administered by oral, parenteral (e.g., intramuscular, intraperitoneal, intravenous, ICV, intracisternal injection or infusion, subcutaneous injection, or implant), by inhalation spray, nasal, vaginal, rectal, sublingual, or topical routes of administration and may be formulated, alone or together, in suitable dosage unit formulations containing conventional non-toxic pharmaceutically acceptable carriers, adjuvants and vehicles appropriate for each route of administration. In addition to the treatment of warm-blooded animals such as mice, rats, horses, cattle, sheep, dogs, cats, monkeys, etc., the compounds of the invention are effective for use in humans.

The pharmaceutical compositions for the administration of the compounds of this invention may conveniently be presented in dosage unit form and may be prepared by any of the methods well known in the art of pharmacy. All methods include the step of bringing the active ingredient into association with the carrier which constitutes one or more accessory ingredients. In general, the pharmaceutical compositions are prepared by uniformly and intimately bringing the active ingredient into association with a liquid carrier or a finely divided solid carrier or both, and then, if necessary, shaping the product into the desired formulation. In the pharmaceutical composition the active object compound is included in an amount sufficient to produce the desired effect upon the process or condition of diseases. As used herein, the term “composition” is intended to encompass a product comprising the specified ingredients in the specified amounts, as well as any product which results, directly or indirectly, from combination of the specified ingredients in the specified amounts.

The pharmaceutical compositions containing the active ingredient may be in a form suitable for oral use, for example, as tablets, troches, lozenges, aqueous or oily suspensions, dispersible powders or granules, emulsions, hard or soft capsules, or syrups or elixirs. Compositions intended for oral use may be prepared according to any method known to the art for the manufacture of pharmaceutical compositions and such compositions may contain one or more agents selected from the group consisting of sweetening agents, flavoring agents, coloring agents and preserving agents in order to provide pharmaceutically elegant and palatable preparations. Tablets contain the active ingredient in admixture with non-toxic pharmaceutically acceptable excipients which are suitable for the manufacture of tablets. These excipients may be for example, inert diluents, such as calcium carbonate, sodium carbonate, lactose, calcium phosphate or sodium phosphate; granulating and disintegrating agents, for example, corn starch, or alginic acid; binding agents, for example starch, gelatin or acacia, and lubricating agents, for example magnesium stearate, stearic acid or talc. The tablets may be uncoated or they may be coated by known techniques to delay disintegration and absorption in the gastrointestinal tract and thereby provide a sustained action over a longer period. For example, a time delay material such as glyceryl monostearate or glyceryl distearate may be employed. They may also be coated by the techniques described in the U.S. Pat. Nos. 4,256,108; 4,166,452; and 4,265,874 to form osmotic therapeutic tablets for control release.

Formulations for oral use may also be presented as hard gelatin capsules wherein the active ingredient is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or an oil medium, for example peanut oil, liquid paraffin, or olive oil.

Aqueous suspensions contain the active materials in admixture with excipients suitable for the manufacture of aqueous suspensions. Such excipients are suspending agents, for example sodium carboxymethylcellulose, methylcellulose, hydroxy-propylmethylcellulose, sodium alginate, polyvinyl-pyrrolidone, gum tragacanth and gum acacia; dispersing or wetting agents may be a naturally-occurring phosphatide, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, or condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethyleneoxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty acids and hexitol anhydrides, for example polyethylene sorbitan monooleate. The aqueous suspensions may also contain one or more preservatives, for example ethyl or n-propyl p-hydroxybenzoate, one or more coloring agents, one or more flavoring agents, and one or more sweetening agents, such as sucrose or saccharin.

Oily suspensions may be formulated by suspending the active ingredient in a vegetable oil, for example arachis oil, olive oil, sesame oil or coconut oil, or in a mineral oil such as liquid paraffin. The oily suspensions may contain a thickening agent, for example beeswax, hard paraffin or cetyl alcohol. Sweetening agents such as those set forth above, and flavoring agents may be added to provide a palatable oral preparation. These compositions may be preserved by the addition of an anti-oxidant such as ascorbic acid.

Dispersible powders and granules suitable for preparation of an aqueous suspension by the addition of water provide the active ingredient in admixture with a dispersing or wetting agent, suspending agent and one or more preservatives. Suitable dispersing or wetting agents and suspending agents are exemplified by those already mentioned above. Additional excipients, for example sweetening, flavoring and coloring agents, may also be present.

The pharmaceutical compositions of the invention may also be in the form of oil-in-water emulsions. The oily phase may be a vegetable oil, for example olive oil or arachis oil, or a mineral oil, for example liquid paraffin or mixtures of these. Suitable emulsifying agents may be naturally-occurring gums, for example gum acacia or gum tragacanth, naturally-occurring phosphatides, for example soy bean, lecithin, and esters or partial esters derived from fatty acids and hexitol anhydrides, for example sorbitan monooleate, and condensation products of the said partial esters with ethylene oxide, for example polyoxyethylene sorbitan monooleate. The emulsions may also contain sweetening and flavoring agents.

Syrups and elixirs may be formulated with sweetening agents, for example glycerol, propylene glycol, sorbitol or sucrose. Such formulations may also contain a demulcent, a preservative and flavoring and coloring agents.

The pharmaceutical compositions may be in the form of a sterile injectable aqueous or oleagenous suspension. This suspension may be formulated according to the known art using those suitable dispersing or wetting agents and suspending agents which have been mentioned above. The sterile injectable preparation may also be a sterile injectable solution or suspension in a non-toxic parenterally-acceptable diluent or solvent, for example as a solution in 1,3-butanediol. Among the acceptable vehicles and solvents that may be employed are water, Ringer's solution and isotonic sodium chloride solution. In addition, sterile, fixed oils are conventionally employed as a solvent or suspending medium. For this purpose any bland fixed oil may be employed including synthetic mono- or diglycerides. In addition, fatty acids such as oleic acid find use in the preparation of injectables.

The compounds of the present invention may also be administered in the form of suppositories for rectal administration of the drug. These compositions can be prepared by mixing the drug with a suitable non-irritating excipient which is solid at ordinary temperatures but liquid at the rectal temperature and will therefore melt in the rectum to release the drug. Such materials are cocoa butter and polyethylene glycols.

For topical use, creams, ointments, jellies, solutions or suspensions, etc., containing the compounds of the present invention are employed. (For purposes of this application, topical application shall include mouthwashes and gargles.)

The pharmaceutical composition and method of the present invention may further comprise other therapeutically active compounds as noted herein which are usually applied in the treatment of the above mentioned pathological conditions.

In the treatment or prevention of conditions which require inhibition of dipeptidyl peptidase-IV enzyme activity an appropriate dosage level will generally be about 0.01 to 500 mg per kg patient body weight per day which can be administered in single or multiple doses. Preferably, the dosage level will be about 0.1 to about 250 mg/kg per day; more preferably about 0.5 to about 100 mg/kg per day. A suitable dosage level may be about 0.01 to 250 mg/kg per day, about 0.05 to 100 mg/kg per day, or about 0.1 to 50 mg/kg per day. Within this range the dosage may be 0.05 to 0.5, 0.5 to 5 or 5 to 50 mg/kg per day. For oral administration, the compositions are preferably provided in the form of tablets containing 1.0 to 1000 mg of the active ingredient, particularly 1.0, 5.0, 10.0, 15.0. 20.0, 25.0, 50.0, 75.0, 100.0, 150.0, 200.0, 250.0, 300.0, 400.0, 500.0, 600.0, 750.0, 800.0, 900.0, and 1000.0 mg of the active ingredient for the symptomatic adjustment of the dosage to the patient to be treated. The compounds may be administered on a regimen of 1 to 4 times per day, preferably once or twice per day.

When treating or preventing diabetes mellitus and/or hyperglycemia or hypertriglyceridemia or other diseases for which compounds of the present invention are indicated, generally satisfactory results are obtained when the compounds of the present invention are administered at a daily dosage of from about 0.1 mg to about 100 mg per kilogram of animal body weight, preferably given as a single daily dose or in divided doses two to six times a day, or in sustained release form. For most large mammals, the total daily dosage is from about 1.0 mg to about 1000 mg, preferably from about 1 mg to about 50 mg. In the case of a 70 kg adult human, the total daily dose will generally be from about 7 mg to about 350 mg. This dosage regimen may be adjusted to provide the optimal therapeutic response.

It will be understood, however, that the specific dose level and frequency of dosage for any particular patient may be varied and will depend upon a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition, and the host undergoing therapy.

Synthetic methods for preparing the compounds of the present invention are illustrated in the following Schemes and Examples. Starting materials are commercially available or may be made according to procedures know in the art or as illustrated herein.

The compounds of the present invention of structural formula (I) can be prepared from intermediates such as those of formulae II and III, using standard reductive amination conditions followed by deprotection to afford compounds of formula (I) wherein Ar and V are as defined above, X is O for oxepanes, X is S for thiepanes, and P is a suitable nitrogen protecting group, such as tert-butoxycarbonyl (Boc), trityl (Tr or CPh₃), benzyloxycarbonyl (Cbz), or 9-fluorenylmethoxycarbonyl (Fmoc). Reductive amination conditions consist of combining the ketone II and amine III in a solvent, such as toluene, tetrahydrofuran, dioxane, dimethylacetamide, ethanol, dichloromethane, dimethylsulfoxide, dichloroethane, or a mixture thereof, and adding a reducing agent such as sodium borohydride, sodium cyanoborohydride, sodium triacetoxyborohydride, or decaborane optionally in the presence of a protic or Lewis acid catalyst, such as acetic acid, hydrochloric acid, p-toluenesulfonic acid, or titanium isopropoxide. The reactions are typically conducted at room temperature, but may be run at elevated temperatures.

Intermediates of formula II may be prepared by a variety of methods familiar to those skilled in the synthetic arts. One route is by ring expansion of tetrahydropyranone or tetrahydrothiopyranone intermediates, such as 1 and 3, respectively (Schemes 1 and 2, respectively) via a Tiffeneu-Demjanov-type intermediate. These ring expansions employ reagents such as diazomethane and various substituted diazomethanes, such as trimethylsilyldiazomethane and benzylsulfonyldiazomethane (see: Okaev, E. V.; Zvonok, A. M. Chemistry of Heterocyclic Compounds, 1995, 31 249) or ethyl diazoacetate and related compounds such as tert-butyl diazoacetate (see: Ye, T.; McKervey, M. A. Chem. Rev. 1994, 94, 1091). As an illustration, an appropriately substituted tetrahydropyranone of formula 1 can be treated with boron trifluoride-diethyl etherate and trimethylsilyldiazomethane (TMSdiazomethane) according to the method of Mori, Y. et. al. (Mori, Y.; Nogami, K.; Hayashi, H.; Noyori, R. J. Org. Chem. 2003, 68, 9050). Protiodesilylation with a suitable acid such as pyridiniump-toluenesulfonate (PPTS) in a protic solvent such as methanol provides ketone IIa (Scheme 1).

The protecting group of IIa (Scheme 1) can be varied at this point by a deprotection and subsequent reprotection to provide intermediate hIb. The protecting group on the amine at C-2 may have affect the diastereoselectivity and yield of of the reductive amination reaction. Reductive amination of ketone IIb with a variety of amines (H—V) of formula III gives a mixture of diastereomeric amines 2 at C-5 (as indicated by an asterisk*). Removal of the amine protecting group followed by chromatographic separation provides pure diastereomers Ie and If.

Scheme 2 illustrates a route to compounds of formulae Ig and Ih via intermediate Ile. These compounds may be prepared by a variety of methods familiar to those skilled in the arts. An appropriately substituted tetrahydrothiopyranone 3 can be treated with boron trifluoride diethyl etherate and TMSdiazomethane to affect a ring expansion. Protiodesilylation with PPTS in methanol provides ketone Ile. Reductive amination of the ketone with a variety of amines of formula III gives a mixture of diastereomeric amines at C-5 (as indicated by asterisk*). Deprotection using standard methods described in T. W. Greene and P. G. M. Wuts, “Protective Groups in Organic Synthesis,” 4^(th) Ed., John Wiley & Sons, Inc., 2007, and subsequent chromatographic separation provides the pure diastereomers Ig and Ih.

In some cases the compounds of structural formula (I) or synthetic intermediates illustrated in the above schemes may be further modified, for example, by manipulation of substituents on Ar or V. These manipulations may include, but are not limited to, reduction, oxidation, alkylation, acylation, and hydrolysis reactions that are commonly known to those skilled in the art.

In some cases the order of carrying out the foregoing reaction schemes may be varied to facilitate the reaction or to avoid unwanted reaction products.

Intermediates of formula 3 in Scheme 2 may be prepared by a variety of methods familiar to those skilled in the synthetic arts. One route is illustrated in Scheme 3. An appropriately substituted aryl nitrostyrene 5 is cyclized with thiol 6 to generate the racemic thiopyran intermediate 7. Reduction of the double bond with sodium borohydride and concomitant epimerization to the trans intermediate 8 is followed by reduction of the nitro group and protection of the amine to give 9. Oxidation of the alcohol such as by regioselective Swern oxidation and chiral resolution provides the ketone intermediate 3.

Intermediates of formula IV are known in the literature or may be conveniently prepared by a variety of methods familiar to those skilled in the art. One common route to prepare tetrahydropyrrolopyrazole IV is illustrated in Scheme 4. Trityl- or Boc-protected pyrrolidinol 11 may be oxidized by a variety of methods, such as the Swem procedure, commonly known to those in the art, to give the ketone 12, which upon treatment and heating with N,N-dimethylformamide dimethylacetal (DMF-DMA) gives 13. Intermediate 14 may then be readily obtained by heating a solution of 13 with a suitable hydrazine in a suitable solvent such as ethanol optionally in the presence of a base such as sodium ethoxide. Substitution of 14 may be done using the appropriate reagent. Intermediate IVa and IVb are obtained by chromatographic separation followed by removal of the protecting group P.

The intermediates and compounds of structural formula I of the present invention can be prepared according to the procedures of the following Schemes and Examples using appropriate materials and are further exemplified by the following specific examples. These specific examples are provided so that the invention might be more fully understood and are to be considered illustrative only and should not be construed as limiting the invention in any way. The Examples further illustrate details for the preparation of the compounds of the present invention. Those skilled in the art will readily understand that known variations of the conditions and processes of the following preparative procedures can be used to prepare these compounds. The instant compounds are generally isolated in the form of their pharmaceutically acceptable salts, such as those described previously hereinabove. The free amine bases corresponding to the isolated salts can be generated by neutralization with a suitable base, such as aqueous sodium hydrogencarbonate, sodium carbonate, sodium hydroxide, and potassium hydroxide, and extraction of the liberated amine free base into an organic solvent followed by evaporation. The amine free base isolated in this manner can be further converted into another pharmaceutically acceptable salt by dissolution in an organic solvent followed by addition of the appropriate acid and subsequent evaporation, precipitation, or crystallization. All temperatures are degrees Celsius unless otherwise noted. Mass spectra (MS) were measured by electron-spray ion-mass spectroscopy. Proton NMR (H-NMR) spectra were measured at 500 MHz, and chemical shifts are provided as parts-per-million (ppm).

The following is a list of abbreviations used in the description of the synthesis of the Intermediates and Examples shown below.

LIST OF ABBREVIATIONS

-   -   Alk alkyl     -   Aq.=aqueous     -   Ar=aryl     -   Boc=tert-butoxycarbonyl     -   BOC₂O=di-tert-butyl Bicarbonate     -   br broad     -   CH₂Cl₂ or DCM dichloromethane     -   d doublet     -   DAST=diethylaminosulfur trifluoride     -   DBU=1,8-diazabicyclo[5.4.0]undec-7-ene     -   DEAD=diethyl azodicarboxylate     -   DIPEA=N,N-dilsopropylethylamine     -   DMA=N,N-dimethylacetamide     -   DMF=N,N-dimethylformamide     -   DMSO=dimethyl sulfoxide     -   ESI=electrospray ionization     -   EtOAc ethyl acetate     -   Et₂O diethyl ether     -   h hours     -   HATU=O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium         hexafluorophosphate     -   HOAc=acetic acid     -   LC-MS=liquid chromatography-mass spectroscopy     -   LiOH=lithium hydroxide     -   m=multiplet     -   MeOH=methyl alcohol (methanol)     -   MgSO₄=magnesium sulfate     -   MS=mass spectroscopy     -   NaOH=sodium hydroxide     -   Na₂SO₄=sodium sulfate     -   NMR=nuclear magnetic resonance spectroscopy     -   P or PG=protecting group     -   Ph=phenyl     -   Rt or RT=room temperature     -   s=singlet     -   sat'd or sat.=saturated     -   SEM=2-trimethylsilylethoxymethyl     -   t=triplet     -   TFA=trifluoroacetic acid     -   THF=tetrahydrofuran     -   Tlc=thin-layer chromatography

Intermediate 1

tert-Butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxooxepan-3-yl]carbamate

To a solution of tert-butyl[(2R,3S)-5-oxo-2-(2,5-difluorophenyl)tetrahydro-2H-pyran-3-yl]carbamate (Intermediate 2 in U.S. Pat. No. 7,678,905, the contents of which are herein incorporated by reference in their entirety) (6 g, 18.3 mmol) in DCM (185 mL) cooled to −78° C. was added boron trifluoride diethyl etherate (9.3 mL, 73.3 mmol) dropwise via syringe. After stirring 10 min at −78° C., trimethylsilyldiazomethane (11 mL, 22 mmol, 2 M in hexane) was added dropwise via syringe and the reaction was stirred 1.5 h at −78° C. The reaction mixture was diluted with diethyl ether and sat. aqueous NaHCO₃, extracted with diethyl ether (×2) and the combined extracts were washed with brine, dried over Na₂SO₄, filtered and concentrated. The resulting oil was dissolved in a mixture of DCM (50 mL) and methanol (50 mL) and pyridiniump-toluenesulfonate (460 mg, 1.83 mmol) was added. The reaction was stirred 18 h at rt, then diluted with DCM and sat. aq. NaHCO₃, washed with sat. aq. NaHCO₃ and brine, then dried over Na₂SO₄, filtered and concentrated. The resulting oil was purified by column chromatography (100 g column, 8% to 70% EtOAc:Hex ramp) to provide the title compound as a white solid.

¹H NMR (500 MHz, CD₃OD) δ 7.13-7.09 (m, 1H); 7.7-6.99 (m, 2H); 4.78 (d, 1H); 4.25 (ddd, 1H); 4.11 (ddd, 1H); 3.83 (t, 1H); 3.37 (t, 1H); 2.81 (ddd, 1H); 2.68 (d, 1H); 2.57 (dd, 1H); 1.24 (s, 9H).

Intermediate 2

tert-Butyl[(2R,3S)-5-oxo-2-(2,4,5-trifluorophenyl)oxepan-3-yl]carbamate

This intermediate was made in a similar manner as that described for Intermediate 1 but using tert-butyl[(2R,3S)-5-oxo-2-(2,4,5-trifluorophenyl)tetrahydro-2H-pyran-3-yl]carbamate (Intermediate 1 in U.S. Pat. No. 7,678,905, the contents of which are herein incorporated by reference in their entirety) as starting material.

¹H NMR (500 MHz, CD₃OD) δ 7.34-7.26 (m, 1H); 7.13-7.06 (m, 1H); 4.74 (d, J=12 Hz, 1H); 4.28-4.21 (m, 1H); 4.10 (td, J=12, 4 Hz, 1H); 3.79 (t, J=12 Hz, 1H); 3.36 (t, J=12 Hz, 1H) 2.76 (m, 1H); 2.71-2.64 (m, 1H); 2.57 (dd, J=12, 4 Hz, 1H); 1.25 (s, 9H).

Intermediate 3

tert-Butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxothiepan-3-yl]carbamate Step A: S-(3,3-Diethoxy-2-hydroxypropyl)ethanethiolate

2-(Diethoxymethyl)oxirane (1.74 mL, 11.2 mmol) was added dropwise to a dry ice/acetone cooled mixture of thiolacetic acid (2.0 mL, 28 mmol) and potassium thiolacetate (300 mg, 2.63 mmol) in methylene chloride (15 mL) over 3 min. After 30 min, the suspension was removed from the dry ice/acetone bath and allowed to warm to room temperature. After 168 h at room temperature, the mixture was added to EtOAc (100 mL) and saturated aq. NaHCO₃ (40 mL), washed 1×40 mL sat'd aq. NaHCO₃, dried with MgSO₄, filtered and evaporated under vacuum to give a light yellow liquid. The crude product was placed onto a silica gel column (2.75×15 cm) and eluted with 1:2 EtOAc/hexanes. Fractions (8 mL fractions) containing the product were combined and evaporated to give the title compound as a clear oil. Literature reference: Charmantray, F.; Dellis, P.; Helaine, V.; Samreth, S.; Hecquet, L., European Journal of Organic Chemistry, 24: 5526-5532 (2006).

HNMR in CDCl₃: 1.25 (t, 6H); 2.36 (s, 3H); 3.02 (dd, 1H); 3.28 (dd, 1H); 3.60 (m, 2H); 3.77 (m, 2H); 4.39 (d, 1H).

Step B: 6-(2,5-Difluorophenyl)-5-nitro-3,6-dihydro-2H-thiopyran-3-ol

A solution of S-(3,3-diethoxy-2-hydroxypropyl) ethanethiolate (1.47 g, 6.62 mmol) was dissolved in water (63.0 mL), 2N HCL (3.3 mL, 6.6 mmol) was added, and the solution was placed in a 50 degree oil bath for 2 h under a nitrogen atmosphere to give thiol Intermediate 6 (see Scheme 3). After cooling in an ice bath, a solution of 1,4-difluoro-2-[(E)-2-nitrovinyl]benzene 5 (1.22 g, 6.6 mmol) in THF (46.5 mL) was added under nitrogen, followed by the dropwise addition of 1N NaOH (19.8 mL, 19.8 mmol) over 10 min to give a hazy orange solution. The mixture was allowed to warm slowly to room temperature and after 24 h was added to a rapidly stirred mixture of EtOAc (720 mL)/water (240 mL)/2N HCl (48 mL). The organic phase was washed with brine (1×100 mL), dried with MgSO4, filtered, and evaporated to give the title compound as a dark colored oil.

HNMR in CDCl₃: [approximately 2:1 mixture of diastereomers] 2.42 (br d, OH); 2.58 (br d, OH); 2.68 (dd, 1H); 2.82 (dd, 1H); 2.83 (dd, 1H); 2.93 (dd, 1H); 5.25 (s, 1H); 5.33 (s, 1H); 6.64 (m, 1H); 6.79 (m, 1H); 6.99 (m, 1H); 7.11 (m, 1H); 7.62 (d, 1H); 7.66 (d, 1H).

Step C: (5S,6R)-6-(2,5-Difluorophenyl)-5-nitrotetrahydro-2H-thiopyran-3-ol

Sodium borohydride (190 mg, 5.03 mmol) 37.8 was added over 10 min to an ice cold solution of 6-(2,5-difluorophenyl)-5-nitro-3,6-dihydro-2H-thiopyran-3-ol (570 mg, 2.08 mmol) in MeOH (25 mL). The mixture was slowly warmed to room temperature and stirred for an additional 18 h. The orange solution was cooled in an ice bath and 2N HCl (2.6 mL, 5.2 mmol) was added dropwise. After 5 min, the solution was added to a mixture of EtOAc (100 mL) and saturated aqueous NaHCO₃ (50 mL), the aqueous layer was re-extracted with additional EtOAc (2×50 mL), the combined EtOAc layers were washed with brine (1×50 mL), dried with MgSO₄, filtered and evaporated to give the title compound as a foam.

HNMR in CDCl₃: [approximately 2:1 mixture of diastereomers] 1.98 (d, 1H); 2.06 (ddd, 1H); 2.16 (ddd, 1H); 2.76 (m, 1H); 2.84 (m, 3H); 3.22 (d, 1H); 4.16 (m, 1H); 4.47 (br s, 1H); 4.57 (d, 1H); 4.65 (d, 1H); 5.13 (ddd, 1H); 5.36 (ddd); 6.98 (m, 1H); 7.04 (m, 2H) and 7.11 (m, 1H).

Step D: tert-Butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-hydroxytetrahydro-2H-thiopyran-3-yl]carbamate

(5S,6R)-6-(2,5-Difluorophenyl)-5-nitrotetrahydro-2H-thiopyran-3-ol (1.75 g, 6.36 mmol) and Zn dust (3.5 g, 53.5 mmol) were suspended in EtOH (50 mL) and cooled in an ice bath. 6N HCl (19.4 mL, 116.4 mmol) was added dropwise over 13 min to give a suspension. After 120 min, 5N NaOH (22.6 mL, 113 mmol) was added to give a heavy suspension. A solution of BOC₂O (2.03 mL, 8.84 mmol) in Et₂O (42 mL) was then added and the suspension was stirred rapidly in the ice bath. After 120 min, additional BOC₂O (200 μL, 0.87 mmol) was added and the solution was slowly warmed to room temperature and stirred for an additional 18 h. The organic phase was decanted and the precipitated solids were extracted with 20% EtOH/EtOAc (4×50 mL), the organic phase was combined and evaporated to give an orange oil. The oil was suspended in 1:1 EtOAc/hexanes and loaded onto a 2.75×30 cm silica gel column eluting with 1:1 EtOAc/hexanes and collecting 8 mL fractions. Fractions containing the product were combined and evaporated to give the title compound.

HNMR in CD₃OD: [a mixture of diastereomers and carbamate rotomers] 1.20 and 1.21 (s, 9H); 1.48 (ddd, 1H), 1.69 (ddd, 1H); 2.04/2.13/2.20/2.30 (m, 1H); 2.58-2.72 (m, 3H); 3.06 (d, 1H); 3.60 (ddd, 1H); 3.93 (m, 2H); 4.0 (ddd, 1H); 4.10 (d, 2H); 4.30 (br s, 1H); 6.60 (br d, 1H); 6.82 (br d, 1H); 6.96 (m, 1H); 7.04 (m, 2H); 7.14 (m, 1H) and 7.30 (m, 1H).

Step E: tert-Butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxotetrahydro-2H-thiopyran-3-yl]carbamate

DMSO (503 μL, 7.09 mmol) was added to a dry ice/acetone cooled solution of oxalyl chloride (253 μL, 2.84 mmol) in methylene chloride (5.0 mL). After 2 min, a solution of tert-butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-hydroxytetrahydro-2H-thiopyran-3-yl]carbamate (490 mg, 1.42 mmol) in methylene chloride (5.0 mL) was added and the mixture was stirred for 30 min. Triethylamine (1.98 mL, 14.2 mmol) was added and the solution was stirred for 10 min and then removed from the dry ice/acetone bath and warmed to room temperature. Methylene chloride (50 mL) and water (30 mL) were added and the organic phase was dried with sodium sulfate, filtered and evaporated to an oil. The residue was placed onto preparative tlc plates, developed with 1:2 EtOAc/hexanes and eluted with EtOAc to give the title compound as a solid. The mixture was resolved by preparative HPLC Chiralpak AD chromatography eluting with 25% IPA/heptane to give the first eluting isomer, namely, tert-butyl[(2S,3R)-2-(2,5-difluorophenyl)-5-oxotetrahydro-2H-thiopyran-3-yl]carbamate and the second eluting title compound isomer, namely, tert-butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxotetrahydro-2H-thiopyran-3-yl]carbamate.

¹H NMR (500 MHz, CD₃OD): [the resolved isomers exist as a mixture of the ketone and isomeric hydrated ketones] 1.22 (s, 9H); 1.23 (s, 9H); 1.63 (ddd, 1H); 2.16 (m, 1H); 2.63-2.78 (m, 3H); 3.02 (d, 1H); 3.74 (d, 1H); 4.08 (d, 1H); 4.21 (m, 1H); 4.35 (m, 1H); 4.48 (d, 1H); 6.97 (m, 1H); 7.04 (in, 1H); 7.11 (m, 1H); 7.16 (m, 1H) and 7.24 (m, 1H).

Step F: tert-Butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxothiepan-3-yl]carbamate

This intermediate was made in a similar manner as that described for Intermediate 1 but using the compound from Step E, namely tert-butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxotetrahydro-2H-thiopyran-3-yl]carbamate, as starting material.

¹H NMR (500 MHz, CD₃OD) δ 7.09-6.97 (m, 3H); 4.34 (d, 1H); 4.09 (t, 1H); 3.30-3.19 (m, 2H); 3.07 (ddd, 1H); 2.96 (dd, (1H); 2.67-2.60 (m, 1H); 2.54 (d, 1H); 1.26 (s, 9H).

Intermediate 4

(6S,7R)-7-(2,4,5-Trifluorophenyl)-6-(tritylamino)oxepan-4-one

Step A:

A solution of tert-butyl[(2R,3S)-5-oxo-2-(2,4,5-trifluorophenyl)oxepan-3-yl]carbamate (Intermediate 2) (642 mg, 1.8 mmol) in 1:1 DCM:TFA (20 mL) was stirred 1 h at rt. The reaction was concentrated to provide the TFA salt of the amine as brown syrup. MS=260.1 (M+H)

Step B:

To a solution of the TFA salt amine from Step A and triphenylmethyl bromide (504 mg, 1.6 mmol) in DCM (20 mL) was added DIPEA (2.27 mL, 13.0 mmol) and the reaction was stirred for 3 h at rt. An aliquot of triphenylmethyl bromide (504 mg, 1.6 mmol) and DIPEA (1 mL, 5.7 mmol) was added and the reaction was stirred 18 h at rt. After a final addition of triphenylmethyl bromide (504 mg, 1.6 mmol), the reaction was stirred 1 h, concentrated and purified by column chromatography (100 g column, 5% to 20% EtOAc:Hex).

¹H NMR (500 MHz, CDCl₃) δ 7.35-7.29 (m, 6H); 7.25-7.15 (m, 9H); 6.97-6.90 (m, 1H); 6.81-6.74 (m, 1H); 4.64 (d, J=10 Hz, 1H); 4.20 (ddd, J=12, 8, 2 Hz, 1H); 3.98 (td, J=12, 4 Hz, 1H); 2.89-2.82 (m, 1H); 2.76-2.67 (m, 1H); 2.54-2.48 (m, 1H); 2.46-2.37 (m, 2H).

Intermediate 5

(6S,7R)-7-(2,5-Difluorophenyl)-6-(tritylamino)oxeoan-4-one

This intermediate was made in a similar manner as that described for Intermediate 4 but using tert-butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxooxepan-3-yl]carbamate (Intermediate 1) as starting material.

¹H NMR (500 MHz, CDCl₃) δ 7.33-7.28 (m, 6H); 7.22-7.14 (m, 9H); 7.06-7.01 (m, 1H); 6.98-6.94 (m, 1H); 6.73-6.68 (m, 1H); 4.65 (d, 1H); 4.21 (ddd, 1H); 3.98 (td, 1H); 2.92-2.86 (m, 1H); 2.75-2.68 (m, 1H); 2.51 (dt, 1H); 2.43-2.35 (m, 2H); 1.95 (d, 1H).

Intermediate 6

Step A: tert-Butyl(3Z)-3-[(dimethylamino)methylene]-4-oxopyrrolidine-1-carboxylate

A solution of tert-butyl 3-oxopyrrolidine-1-carboxylate (40 g, 216 mmol) was treated with DMF-DMA (267 g, 2241 mmol) and heated at 105° C. for 40 min. The solution was cooled and evaporated under reduced pressure and the resulting orange solid was treated with hexane (200 mL) and cooled in a refrigerator for 3 days. The resulting brownish-yellow solid obtained as such was collected by filtration, dried and used in the next step without further purification.

Step B: 1,4,5,6-Tetrahydropyrrolo[3,4-c]pyrazole

A solution of hydrazine (3 mL) and tert-butyl(3Z)-3-[(dimethylamino)methylene]-4-oxopyrrolidine-1-carboxylate (19.22 g) in ethanol (40 mL) was heated at 85° C. in a sealed tube for 4 h. Solvent was removed under reduced pressure, and the residue was triturated with dichloromethane (160 mL) and ethyl acetate (15 mL). The resulting solid was filtered. The filtrate was concentrated and the resulting solid was triturated again and filtered. The combined solids were treated with 4N hydrochloric acid (250 mL) in methanol and stirred for 6 h. The reaction mixture was concentrated and dried. The resulting solid was treated again for 6 h with 4N hydrochloric acid (250 mL) in methanol. After concentration and drying, the resulting hydrochloride salt was treated with ammonia in methanol (2N, 300 mL) and ammonium hydroxide solution in water (28%, 30 mL) and concentrated to dryness. The solid obtained was treated with methanol (70 mL) and water (5 mL) and purified in three batches on Biotage Horizon® system (silica, gradient 5-17% methanol containing 10% concentrated ammonium hydroxide in ethyl acetate) to yield 1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole.

¹H NMR (500 MHz, CD₃OD): δ 4.04 (d, 4H); 7.39 (s, 1H).

Intermediate 7

Step A: tert-Butyl 4,6-dihydropyrrolo[3,4-c]pyrazole-5(1H)-carboxylate

To a suspension of 1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole (Intermediate 6) (207 g) in CH₂Cl₂ (1.0 L) was added triethylamine (147 mL, 1058 mmol) followed by liquid di-tert-butyl dicarbonate (95 mL, 445 mmol) via an additional funnel over 45 min. The mixture was stirred at RT overnight. The mixture was then transferred into a separation funnel and washed in succession with 3×500 mL 2.0N HCl, 2×500 mL 10% NaOH, and 400 mL of brine. The mixture was then dried over Na₂SO₄ and evaporated to give Intermediate 4 as a brown solid. LC-MS 210.1 [M+1].

Step B: tert-Butyl 2-(2-amino-2-oxoethyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

A 2 L three neck flask fitted with a thermometer, a mechanical stirrer and an addition funnel was charged with a suspension of tert-butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (18.01 g, 86.5 mmol) in anhydrous acetonitrile (1.0 L). Sodium hydride (60% dispersion in oil, 4.15 g, 104 mmol) was added to the suspension in one portion under nitrogen. The reaction was stirred at room temperature for 2 h. The resulting white suspension was then cooled in an ice bath and iodoacetamide (31.95 g, 173 mmol) was added. The ice bath was then removed and the mixture was stirred 18 h at room temperature. The mixture was quenched with water (50 mL) and the solvent was removed under reduced pressure. The residue was partitioned between diluted NaCl (50 mL brine and 100 mL water) and 1.0 L EtOAc. The aqueous layer was extracted with 2×1.0 EtOAc. The organic layers were combined and dried over Na₂SO₄ and solvent was evaporated under reduced pressure. Crude material was purified on silica gel eluting with 20-50% EtOAc/CH₂Cl₂ to wash out excess iodoacetamide, and then with 2-10% MeOH/CH₂Cl₂ to afford a mixture of the two products which were separated on a chiral AD column by eluting with 30% MeOH/CO₂ to afford the title compound (less mobile fraction). LC-MS=267.32 [M+1].

Step C: 2-(5,6-Dihydropyrrolo[3,4-c]pyrazol-2(4H)-yl)acetamide

To a solution of tert-butyl 2-(2-amino-2-oxoethyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (25.04 g, 94 mmol) in CH₂Cl₂ (200 mL) was added trifluoroacetic acid (100 mL) at 0° C. The mixture was stirred at RT for 3 h. The mixture was concentrated and neutralized with 25% MeOH (containing 10% NH₄OH)/CH₂Cl₂. The residue was then purified on two 65i Biotage® columns eluting with 12.5-25% MeOH (containing 10% NH₄OH)/CH₂Cl₂ to give Intermediate 7 as a free base. LC-MS=167.10 [M+1].

Intermediate 8

Methyl 2-(5,6-dihydro-4H-pyrrolo[3,4-c]pyrazol-2-yl)acetate hydrochloride salt

A suspension of Intermediate 7 (499 mg, 2.46 mmol) in 4M HCl in methanol (20 mL, 80 mmol) was stirred at room temperature for 18 h to give a clear solution. The solvents were evaporated under vacuum to give an amber-colored solid. MS=182.16 [M+1].

Intermediate 9

2-(2-Hydroxy-2-methylpropyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazol-5-ium trifluoroacetate salt

To a stirred solution of tert-butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (Step A of Intermediate 7) (35 g, 167 mmol) in DMF (500 mL) at 0° C. under N₂ was added sodium hexamethyldisilazide in THF (351 mL, 351 mmol) and the mixture was stirred at 0° C. for 30 min. Isobutylene oxide (74.3 mL, 836 mmol) was then slowly added. The solution was stirred at 0° C. for 0.5 h and then stirred at room temperature for 1 h. The solution was heated to 80° C. for 100 min in a microwave oven, cooled to room temperature and evapoarted under vacuum. The residue was purified by column chromatography on silica gel, eluting with a gradient of 0% to 6% CH₂Cl₂/MeOH (containing 10% NH₄OH) to give a mixture of two regioisomers. The mixture of two regioisomers A and B was resolved by chromatography on a ChiralPak AD-H column eluting with 4-40% MeOH/CO₂ to give isomer A as the faster eluting isomer and isomer B as the slower eluting isomer. NMR (500 MHz, CD₃OD) for isomer B: δ7.42 (d, 1H); 4.42 (s, 2H); 4.41 (s, 2H); 4.07 (s, 2H); 1.51 (d, 9H); 1.16 (s, 6H). LC-MS: 226.27 (M+1-56).

The desired isomer B was treated with 1:1 TFA/CH₂Cl₂ for 1 h to give the title compound. NMR (500 MHz, CD₃OD): δ7.55 (s, 1H); 4.43 (s, 2H); 4.39 (s, 2H); 4.10 (s, 2H); 1.17 (s, 6H). LC-MS: 182.31 (M+1).

Intermediate 10

tert-Butyl 2-(2-fluoro-2-methylpropyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

To a dry flask filled with N₂ was added 7.35 g (26.8 mmol) of isomer B, Intermediate 9, in 40 ml of CH₂Cl₂, cooled to −78° C., added slowly 19.45 ml (147 mmol) of DAST reagent. The mixture was stirred at −78° C. for 40 min. The reaction was quenched by the dropwise addition of water at −78° C., warmed to ambient temperature and then neutralized by adding sattd. NaHCO₃ aqueous solution. The resulting mixture was partitioned and extracted by CH₂Cl₂ twice, dried over anhydrous Na₂SO₄ and the solvents were removed under vacuum. The residue was chromatographed on a Biotage® system (silica gel, 65i column, 15 to 50% EtOAc/Hexane gradient) to yield the title compound. MS=284.1 (M+1).

Intermediate 11

Step A: tert-Butyl 2-{[2-(trimethylsilybethoxy]methyl}-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

To a stirred solution of tert-butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (20 g, 96 mmol) in DMF (200 mL) at 0° C. was added sodium hydride (4.21 g, 105 mmol). After stirring for 1 h at RT, 2-trimethylsilylethoxymethyl chloride (SEM-Cl) (4.65 mL, 26.3 mmol) was added. The resulting mixture was stirred at RT overnight. The mixture was quenched with saturated NH₄OH, and the solvents were removed. The residue was diluted with ethyl acetate (500 mL), washed with water, brine, dried over anhydrous sodium sulfate and concentrated. The residue was purified by column chromatography on a silica gel Biotage 65i® column, eluting with 0 to 20% ethyl acetate in hexanes to give the title compound as a colorless gum. LC-MS: 340.1 (M+H)

Step B: 5-tert-Butyl-3-ethyl-2-{[2-(trimethylsilyl)ethoxy]methyl}-2,6-dihydropyrrolo[3,4-c]pyrazole-3,5(4H)-dicarboxylate

To a stirred solution of the tert-butyl 2-{[2-(trimethylsilyl)ethoxy]methyl}-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (26 g, 77 mmol) in THF (400 mL) at −78° C. under nitrogen was added a solution of n-butyllithium (1.6M, 57.4 mL, 92 mmol). The mixture was stirred at −78° C. for 40 min, ethyl chloroformate (9.19 mL, 96 mmol) was added, and the mixture was stirred at −78° C. for an additional 4 h. The mixture was quenched with saturated ammonium chloride (200 mL) and water (50 mL), extracted with ethyl acetate (500 mL), washed with brine (200 mL), dried (Na₂SO₄), filtered and concentrated. The residue was purified by column chromatography on a silica gel Biotage 65i® column eluting with 0-25% EtOAc/hexanes to give the title compound. LC-MS: 412.2 (M+H).

Step C: 5-(tert-Butoxycarbonyl)-2-{[2-(trimethylsilyl)ethoxy]methyl}-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxylic acid

To a stirred mixture of product obtained in Step B (2.2 g, 5.35 mmol) in 1,4-dioxane (75 mL) was added lithium hydroxide (1 M, 26.7 mL). The reaction was stirred at 35° C. for 24 h. Solvents were removed, and the residue was washed with hexanes (75 mL). The aqueous layer was diluted with water, acidified with 2N HCl to pH about 3, extracted with EtOAc (2×200 mL). The organic layers were washed with water, brine, dried over Na₂SO₄ and concentrated to give the crude product. LC-MS: 384.2 (M+H).

Step D: tert-Butyl 3-carbamoyl-2-{[2-(trimethylsilyl)ethoxy]methyl}-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

To a stirred solution of the product obtained in Step C (600 mg, 1.564 mmol) in DMF (15 mL) was added DIPEA (1.366 mL, 7.82 mmol) and ammonium chloride (2.5 g, 46.9 mmol). After stirring for 30 min, HATU (1190 mg, 3.13 mmol) was added. The resulting mixture was stirred at room temperature under nitrogen for 22 h, diluted with ethyl acetate (200 mL), washed with 1N hydrochloric acid (2×100 mL), dried over Na₂SO₄, filtered and concentrated to give the crude title compound. LC-MS: 383.2 (M+H).

Step E: 2,4,5,6-Tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide hydrochloride salt

The product from Step D (6.85 g, 17.91 mmol) was dissolved in 4N HCl (100 mL, 400 mmol) and stirred at room temperature for 18 h. The suspension was evaporated and the residue was filtered using methylene chloride to give Intermediate 11. LC-MS: 153.1 (M+H).

Intermediate 12

1-Phenyl-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole

Step A:

A suspension of tert-butyl(3Z)-3-[(dimethylamino)methylidene]-4-oxopyrrolidine-1-carboxylate (1.0 g, 4.16 mmol) and phenylhydrazine (490 μL, 5 mmol) in ethanol (10 mL) was heated to 110° C. for 5 h. The reaction mixture was cooled to rt and purified by column chromatography (50 g column, elution with 20% EtOAc/DCM).

Step B:

The product from Step A was dissolved in 4 M HCl and stirred 2 h at rt. The reaction mixture was concentrated and purified by column chromatography (0% to 5% methanol containing 10% ammonium hydroxide: DCM) to provide the title compound.

¹H NMR (500 MHz, CDCl₃) δ 7.60-7.56 (m, 2H); 7.50-7.44 (m, 3H); 7.31 (t, 1H); 4.31 (s, 2H); 4.03 (s, 2H). MS=186.1 (M+H)

Intermediate 13

1-[2-(Trifluoromethyl)pyrimidin-4-yl]-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole

Step A:

To a 0° C. solution of tert-butyl 4,6-dihydropyrrolo[3,4-c]pyrazole-5(1H)-carboxylate (0.5 g, 2.4 mmol) in THF (5 mL) was added sodium hydride (100 mg, 2.4 mmol, 60% dispersion in mineral oil) and 4-chloro-2-(trifluoromethyl)pyrimidine (436 mg, 2.4 mmol). The reaction was heated to 55° C. and stirred 18 h, then diluted with a mixture of brine and water (1:1) and EtOAc, extracted with EtOAc (×2), dried over Na₂SO₄, filtered and concentrated. The resulting oil was purified by column chromatography (50 g column, 10% to 80% EtOAc/Hex ramp) to provide regioisomer A as the faster eluting and regioisomer B as the slower eluting.

Step B:

The desired regioisomer B was treated with 1:1 TFA/CH₂Cl₂ (8 mL) for 1 h and concentrated in vacuo. The resulting TFA salt was loaded on polymeric strong cation resin, washed with methanol, eluted with 1:1 methanol/ammonium hydroxide and concentrated to provide the title compound.

¹H NMR (500 MHz, CDCl₃) δ 8.93 (d, 1H); 8.04 (d, 1H); 7.62 (s, 1H); 4.41 (t, 2H); 3.99 (t, 2H). MS=256.1 (M+H)

Intermediate 14

1-[5-(Trifluoromethyl)pyridin-2-yl]-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole

This Intermediate was made according to the route described for Intermediate 13 by replacing 4-chloro-2-(trifluoromethyl)pyrimidine with 4-chloro-2-(trifluoromethyl)pyrimidine.

¹H NMR (500 MHz, CD₃OD) δ 8.75 (s, 1H); 8.26 (dd, 1H); 8.10 (d, 1H); 7.65 (s, 1H); 4.76 (s, 2H); 4.33 (s, 2H). MS=255.1 (M+H)

Intermediate 15

1-(Pyrimidin-2-yl)-1,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole

This intermediate was made according to the route described for Intermediate 13 by replacing 4-chloro-2-(trifluoromethyl)pyrimidine with 2-bromopyrimidine.

¹H NMR (500 MHz, CD₃OD) δ 8.77 (d, 2H); 7.57 (s, 1H); 7.35 (t, 1H); 4.42 (br s, 2H); 4.03 (br s, 2H). MS=188.1 (M+H)

Intermediate 16

2-(Pyrimidin-2-yl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole

This intermediate was made according to the route described for Intermediate 13 by replacing 4-chloro-2-(trifluoromethyl)pyrimidine with 2-bromopyrimidine. The faster eluting regioisomer was isolated and deprotected in a similar manner as for Intermediate 13.

¹H NMR (500 MHz, CD₃OD) δ 8.75 (d, 2H); 8.37 (s, 1H); 7.33 (t, 1H); 4.05 (d, 4H). MS=188.1 (M+H)

Intermediate 17

2-(Cyclopropylsulfonyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole trifluoroacetic acid salt Step A: tert-Butyl 2-(cyclopentylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

To a suspension of sodium hydride (60% dispersion in oil, 1.55 g, 38.7 mmol) in anhydrous acetonitrile (200 mL) was added to tert-butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (5.3 g, 25.5 mmol) in one portion under nitrogen at room temperature. The reaction mixture was stirred at room temperature for 2 h. To the resulting white suspension was slowly added cyclopropanesulfonyl chloride (6.9 g, 49.1 mmol) and the mixture was stirred at room temperature for 18 h, quenched with water (120 mL) and the layers were separated. The aqueous layer was then extracted with dichloromethane (2×100 mL). The combined organic layers were dried over anhydrous sodium sulfate and concentrated under reduced pressure. The crude material was purified on silica chromatography (300 g Biotage™ column) and eluted with 15-80% ethyl acetate in hexanes to yield the title compound and tert-butyl 1-(cyclopentylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate as a white solid. LC/MS: 314.2 (M+1).

Step B: 2-[(1-Methylcyclopropyl)sulfonyl]-2,4,5,6-tetrahydropyrrolo[3,4c]pyrazole hydrochloride salt

To a solution of tert-butyl 2-(cyclopropylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (250 mg, 0.80 mmol) in THF (10 mL) cooled to −78° C. was added sodium bis(trimethylsilyl)amide (1.2 mL, 1.2 mmol, 1 M in THF). The mixture was stirred for 15 min at −78° C. and iodomethane (150 μL, 2.4 mmol) was added. The reaction was allowed to warm to 0° C. over 3 h, then quenched with sat. NH₄Cl and partitioned between water and EtOAc. The aqueous phase was extract with EtOAc (×3) and the combined organic extracts dried over Na₂SO₄, filtered and concentrated to provide a yellow solid. The solid was purified by column chromatography (50 g column, 0%-20% EtOAc:Hex ramp) to provide a white solid.

Step C:

The white solid from Step B was dissolved in 4 M HCl in methanol (10 mL) and stirred 4 h at rt. The reaction was concentrated to provide the title compound. MS=228.1 (M+H)

Intermediate 18

3-Methyl-2-[(1-methylcyclopropyl)sulfonyl]-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole trifluoroacetate salt

Step A:

To a solution of tert-butyl 2-(cyclopropylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate (250 mg, 0.8 mmol) in THE (10 mL) cooled to −78° C. was added n-butyllithium (1.12 mL, 2.8 mmol, 2.5M in hexane). The reaction was stirred 15 min at −78° C. then iodomethane (500 μL, 7.98 mmol) was added. After 2 h at −78° C., the reaction was quenched with sat. ammonium chloride and water, extracted with EtOAc (×3), dried over Na₂SO₄, filtered, and concentrated. The resulting oil was purified by column chromatography (50 g, 5% to 40% EtOAc:Hex ramp) to provide a white solid. MS=342.1 (M+H).

Step B:

The material from Step A was dissolved in a 1:1 mixture of TFA:DCM (4 mL) and stirred 1 h at rt. The reaction was concentrated to provide the title compound. MS=242.1 (M+H)

Intermediate 19

2-(Methylsulfonyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole benzenesulfonic acid salt Step A: tert-Butyl(3Z)-3-[(dimethylamino)methylene]-4-oxopyrrolidine-1-carboxylate

tert-Butyl 3-oxopyrrolidine-1-carboxylate (40 g, 216 mmol) was treated with N,N-dimethylformamide dimethyl acetal (267 g, 2241 mmol) and heated at 105° C. for 40 min. The solution was cooled and evaporated under reduced pressure and the resulting orange solid was treated with hexane (200 mL) and cooled in the refrigerator for 64 h. The resulting brownish-yellow solid obtained as such was collected by filtration, dried and used in the next step without further purification. LC/MS: 241.1 (M+1).

Step B: tert-Butyl 2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

A solution of hydrazine (3 mL) and tert-butyl(3Z)-3-[(dimethylamino)methylene]-4-oxopyrrolidine-1-carboxylate (19.22 g) in ethanol (40 mL) was heated at 85° C. in a sealed tube for 4 h. Solvent was removed under reduced pressure, and the residue was triturated with dichloromethane (160 mL) and ethyl acetate (15 mL). The resulting solid was filtered. The filtrate was concentrated and the resulting solid was triturated again and filtered. The combined solids were used without further purification. LC/MS: 210.1 (M+1).

Step C: tert-Butyl-(methylsulfonyl)]-2,6-dihydropyrrolo[3,4-c]pyrazole-5(4H)-carboxylate

A solution of the product from Step B (100 g, 478 mmol) in anhydrous N,N-dimethylformamide (1.0 L) was cooled to −40° C. and treated with 1 M sodium bis(trimethylsilyl)amide in tetrahydrofuran (502 mL, 502 mmol) slowly over 20 min. The temperature warmed to −30° C. during the addition and the mixture was stirred at this temperature for 1 h. Methanesulfonyl chloride (44.7 mL, 573 mmol) was slowly added via addition funnel and stirred for an additional 1.5 h at −30 to −40° C. The reaction mixture was quenched with ice (3.5 kg), slowly warmed to ambient temperature and stirred for 48 h. The resulting white solid was filtered, washed with water and suction dried to afford the title compound. LC/MS: 288.1 (M+1).

Step D: 2-(Methylsulfonyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole benzenesulfonic acid salt

To the product from Step C (87 g, 303 mmol) in isopropyl acetate (1 L) was added benzensulfonic acid (71.8 g, 454 mmol) and the mixture warmed to 40° C. and stirred for 2 h. The mixture was cooled to ambient temperature and stirred for 16 h to give an off-white slurry. The solid was filtered, washed with isopropyl acetate, and suction dried to afford the title compound as a white solid. LC/MS: 188.1 (M+1).

Other Intermediates H—V may be prepared according to procedures described in U.S. Pat. No. 7,482,336; U.S. Pat. No. 7,678,905; US 2008/0076773 (Mar. 27, 2008); US 2009/0105284 (Apr. 23, 2009): US 2009/0270467 (Oct. 29, 2009); WO 2007/097931 (Aug. 30, 2007); US 2009/0209544 (Aug. 20, 2009); and WO 2009/025784 (Feb. 26, 2009; the contents of each of which are incorporated by reference in their entirety.

EXAMPLE 1

(2R,3S,5R)-2-(2,5-Difluorophenyl)-5-[2-(methylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazol-5(4H)-yl]oxepan-3-amine trifluoroacetate salt

Step A:

To a 0° C. solution of (6S,7R)-7-(2,5-difluorophenyl)-6-(tritylamino)oxepan-4-one (Intermediate 5) (150 mg, 0.31 mmol) and 2-(methylsulfonyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole (Intermediate 19) (64 mg, 0.34 mmol) in DCM (3 mL) was added titanium(IV) isopropoxide (91 μL, 0.31 mmol). The reaction was stirred for 10 min at 0° C., then sodium cyanoborohydride (310 μL, 0.31 mmol, 1M in THF) was added. The reaction was heated to 50° C. for 1 h, then cooled to rt for 18 h and concentrated to approximately 1 mL. The resulting solution was purified by preparative thin layer chromatography (4×1000 micron PTLC plates using 10% methanol (containing 2N NH₃) in DCM as a developing solvent). The major band was removed, eluted with 1:1 methanol/DCM and evaporated. Examination of the oil by ¹H NMR showed an approximately 4:1 mixture of diastereomeric amines at C-5.

Step B:

The mixture of diastereomers from Step A was dissolved in 4M HCl in methanol (2 mL) and stirred for 15 min at rt. The reaction mixture was concentrated and the residue was purified by preparative thin layer chromatography (4×250 micron PTLC plates using 20% methanol (containing 2N NH₃) in EtOAc as a developing solvent). The less polar band was removed and eluted with 1:1 methanol/DCM. The solvent was evaporated and the residue was lyophilized from a mixture of acetonitrile and 1% TFA in water to give the title compound as a white solid.

¹H NMR (500 MHz, CD₃OD) δ 7.87 (s, 1H); 7.26-7.23 (m, 1H); 7.25-7.10 (m, 2H); 4.56 (d, 1H); 4.08 (ddd, 1H); 4.00-3.91 (m, 41-1); 3.87 (ddd, 1H); 3.35-3.30 (m, 5H); 2.32-2.28 (m, 2H); 2.00-1.90 (m, 2H). MS=413.1 (M+H)

EXAMPLE 2

(2R,3S,5R)-5-[2-(1-Methylcyclopropyl)sulfonyl-4,6-dihydropyrrolo[3,4-c]pyrazol-5-yl]-2-(2,4,5-trifluorophenyl)oxepan-3-amine trifluoroacetate salt

This Example was prepared in a similar manner as Example 1, except that (6S,7R)-7-(2,4,5-trifluorophenyl)-6-(tritylamino)oxepan-4-one (Intermediate 4) was substituted for Intermediate 5 and 2-[(1-methylcyclopropyl)sulfonyl]-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole (Intermediate 17) was substituted for 2-(methylsulfonyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole in the reductive amination.

¹H NMR (500 MHz, CD₃OD) δ 7.92 (s, 1H), 7.57-7.50 (m, 1H); 7.30-7.23 (m, 1H); 4.76 (d, 1H); 4.15-3.98 (m, 5H); 3.92-3.86 (m, 1H); 3.70 (td, 1H); 3.45 (td, 1H); 2.49-2.43 (m, 1H); 2.38-2.30 (m, 1H); 2.10 (q, 1H); 2.04-1.92 (m, 1H); 1.65-1.60 (m, 2H); 1.36 (s, 3H); 1.04-1.00 (m, 2H). MS=471.0 (M+H)

EXAMPLE 3

5-[(4R,6S,7R)-6-Amino-7-(2,5-difluorophenyl)oxepan-4-yl]-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carbonitrile trifluoroacetate salt

Step A:

Reductive amination of Intermediate 5 with 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole-3-carboxamide (Intermediate 11) as described in Example 1 provided a mixture of diastereomers comprised of: 5-[(4R,6S,7R)-7-(2,5-difluorophenyl)-6-(tritylamino)oxepan-4-yl]-4,6-dihydro-2H-pyrrolo[3,4-c]pyrazole-3-carboxamide and 5-[(4S,6S,7R)-7-(2,5-difluorophenyl)-6-(tritylamino)oxepan-4-yl]-4,6-dihydro-2H-pyrrolo[3,4-c]pyrazole-3-carboxamide.

Step B:

The mixture of diastereomers from Step A (30 mg, 0.05 mmol) was dissolved in pyridine (1 mL) and phosphorous oxychloride (9 μL, 0.01 mmol) was added. The resulting mixture was stirred for 2 h at rt, quenched with water (50 μL) and concentrated. The residue was purified by preparative thin layer chromatography (4×500 micron PTLC plates using 20% methanol (containing 2N NH₃) in DCM as a developing solvent).

Step C:

The mixture of diastereomers from Step B was dissolved in 4 M HCl in dioxane and stirred 1 h at rt. The reaction mixture was concentrated and the residue was purified by preparative thin layer chromatography (2×250 micron PTLC plates using 20% MeOH (containing 2 N NH₃) in ethyl acetate as a developing solvent). The appropriate band was removed and eluted with 1:1 methanol/DCM. The solvent was evaporated and residue was repurified by PTLC (2×250 micron PTLC plates using 20% MeOH (containing 2 N NH₃) in DCM as a developing solvent). The appropriate band was removed, eluted with 1:1 methanol/DCM, and evaporated to give the title compound.

¹H NMR (500 MHz, CD₃OD) δ 7.22-7.19 (m, 1H); 7.21-7.05 (m, 2H); 4.46 (d, 2H); 4.08-3.99 (m, 5H), 3.84 (ddd, 1H); 3.32-3.28 (m, 1H), 3.14 (ddd, 1H), 2.29-2.21 (m, 2H); 1.93-1.84 (m, 2H). MS=360.1 (M+H)

EXAMPLE 4

(2R,3S,5R)-2-(2,5-Difluorophenyl)-5-[2-(methylsulfonyl)-2,6-dihydropyrrolo[3,4-c]pyrazol-5(4H)-yl]thiepan-3-amine trifluoroacetate salt

Step A:

To a solution of tert-butyl[(2R,3S)-2-(2,5-difluorophenyl)-5-oxothiepan-3-yl]carbamate (Intermediate 3) (55 mg, 0.1.5 mmols) and 2-(methylsulfonyl)-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazole (Intermediate 19) (35 mg, 0.19 mmol) in DCM (1.5 mL) and DMSO (100 μL) was added titanium(IV) isopropoxide (135 μL, 0.46 mmol). The reaction was stirred for 10 min at 0° C., then sodium cyanoborohydride (462 μL, 0.46 mmol, 1M in THF) was added and the reaction was heated to 50° C. for 3 h. The reaction mixture was concentrated to approximately 0.5 mL and purified by preparative thin layer chromatography (2×1000 micron PTLC plates using 10% MeOH (containing 2 N NH₃) in DCM as a developing solvent). The major band was removed, eluted with 1:1 methanol/DCM and evaporated. Examination of the oil by ¹H NMR showed an approximately 4:1 mixture of diastereomeric amines at C-5.

Step B:

The mixture of diastereomers from Step A was dissolved in a mixture of TFA (2 mL) and DCM (3 mL) and stirred for 1 h at rt. The solvents were evaporated and the residue was purified by preparative thin layer chromatography (4×500 micron PTLC plates using 10% MeOH (containing 2 N NH₃) in ethyl acetate as a developing solvent). The less polar band was removed and eluted with 1:1 methanol/DCM. The solvent was evaporated and the residue was freeze-dried from a mixture of acetonitrile and 1% TFA in water to give the title compound as a white solid.

¹H NMR (500 MHz, CD₃OD) δ 7.88 (s, 1H); 7.27-724 (m, 1H); 7.26-7.18 (m, 1H); 7.17-7.09 (m, 1H); 4.08-3.90 (m, 5H); 3.77-3.68 (m, 2H); 3.35 (s, 3H); 3.12 (ddd, 1H); 3.00 (ddd, 1H); 2.28-2.18 (m, 2H); 2.07-1.93 (m, 2H). MS=429.0 (M+H)

The following additional Examples were prepared by substituting the appropriate H—V intermediate in the reductive amination step with Intermediate 3, Intermediate 4, or Intermediate 5 as detailed in Examples 1-4. The amine protecting group was then removed as in Example 1 or Example 4 for X═O or X═S, respectively.

MS Example R¹ X V M + 1 5 H O

335.2 6 F O

431.0 7 H O

413.1 8 H O

413.1 9 H O

411.2 10 H O

480.1 11 H O

481.0 12 H O

378.1 13 H O

407.1 14 H O

439.0 15 F O

457.0 16 H O

452.97 17 H O

467.0 18 H O

387.1 19 H O

415.0 20 F O

433.0 21 H O

417.1 22 H O

349.1 23 H O

361.1 24 H S

386.1 Example of a Pharmaceutical Formulation

As a specific embodiment of an oral pharmaceutical composition, a 100 mg potency tablet is composed of 100 mg of any one of the Examples, 268 mg microcrystalline cellulose, 20 mg of croscarmellose sodium, and 4 mg of magnesium stearate. The active, microcrystalline cellulose, and croscarmellose are blended first. The mixture is then lubricated by magnesium stearate and pressed into tablets.

While the invention has been described and illustrated with reference to certain particular embodiments thereof, those skilled in the art will appreciate that various adaptations, changes, modifications, substitutions, deletions, or additions of procedures and protocols may be made without departing from the spirit and scope of the invention. For example, effective dosages other than the particular dosages as set forth herein above may be applicable as a consequence of variations in responsiveness of the mammal being treated for any of the indications with the compounds of the invention indicated above. The specific pharmacological responses observed may vary according to and depending upon the particular active compounds selected or whether there are present pharmaceutical carriers, as well as the type of formulation and mode of administration employed, and such expected variations or differences in the results are contemplated in accordance with the objects and practices of the present invention. It is intended, therefore, that the invention be defined by the scope of the claims which follow and that such claims be interpreted as broadly as is reasonable. 

What is claimed is:
 1. A compound of structural formula I:

or a pharmaceutically acceptable salt thereof; wherein X is O or S; V is selected from the group consisting of:

Ar is phenyl optionally substituted with one to five R¹ substituents; each R¹ is independently selected from the group consisting of halogen, cyano, hydroxy, C₁₋₆ alkyl, optionally substituted with one to five fluorines, and C₁₋₆ alkoxy, optionally substituted with one to five fluorines; each R² is independently selected from the group consisting of hydrogen, hydroxy, halogen, cyano, heteroaryl, C₁₋₁₀ alkoxy, wherein alkoxy is optionally substituted with one to five substituents independently selected from fluorine and hydroxy, C₁₋₁₀ alkyl, wherein alkyl is optionally substituted with one to five substituents independently selected from fluorine and hydroxy, C₂₋₁₀ alkenyl, wherein alkenyl is optionally substituted with one to five substituents independently selected from fluorine and hydroxy, (CH₂)-aryl, wherein aryl is optionally substituted with one to five substituents independently selected hydroxy, halogen, cyano, nitro, CO₂H, C₁₋₆ alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines, (CH₂)-heteroaryl, wherein heteroaryl is optionally substituted with one to three substituents independently selected from hydroxy, halogen, cyano, nitro, CO₂H, C₁₋₆ alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines, (CH₂)-heterocyclyl, wherein heterocyclyl is optionally substituted with one to three substituents independently selected from oxo, hydroxy, halogen, cyano, nitro, CO₂H, C₁₋₆ alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines, (CH₂)—C₃₋₆ cycloalkyl, wherein cycloalkyl is optionally substituted with one to three substituents independently selected from halogen, hydroxy, cyano, nitro, CO₂H, C₁₋₆ alkyloxycarbonyl, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines, (CH₂)—COOH, (CH₂)—COOC₁₋₆ alkyl, (CH₂)—NR⁴R⁵, (CH₂)—CONR⁴R⁵, (CH₂)—OCONR⁴R⁵, (CH₂)—SO₂NR⁴R⁵, (CH₂)—SO₂R⁶, (CH₂)—NR⁷SO₂R⁶, (CH₂)—NR⁷CONR⁴R⁵, (CH₂)—NR⁷COR⁷, and (CH₂)—NR⁷CO₂R⁶; wherein any individual methylene (CH₂) carbon atom is optionally substituted with one to two substituents independently selected from fluorine, hydroxy, C₁₋₄ alkyl, and C₁₋₄ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines; R^(3a), R^(3b) and R^(3c) are each independently hydrogen or C₁₋₄ alkyl optionally substituted with one to five fluorines; R⁴ and R⁵ are each independently selected from the group consisting of hydrogen, (CH₂)-phenyl, (CH₂)—C₃₋₆ cycloalkyl, and C₁₋₆ alkyl, wherein alkyl is optionally substituted with one to five substituents independently selected from fluorine and hydroxy and wherein phenyl and cycloalkyl are optionally substituted with one to five substituents independently selected from halogen, hydroxy, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines; or R⁴ and R⁵ together with the nitrogen atom to which they are attached form a heterocyclic ring selected from azetidine, pyrrolidine, piperidine, piperazine, and morpholine wherein said heterocyclic ring is optionally substituted with one to three substituents independently selected from halogen, hydroxy, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines; each R⁶ is independently C₁₋₆ alkyl, wherein alkyl is optionally substituted with one to five substituents independently selected from fluorine and hydroxyl; R⁷ is hydrogen or R⁶; and R⁸ is selected from the group consisting of -hydrogen, —(CH₂)-phenyl, —(CH₂)-heteroaryl, —(CH₂)—C₃₋₆ cycloalkyl, —SO₂C₁₋₆ alkyl, —CH₂SO₂C₁₋₆ alkyl, —SO₂C₃₋₆ cycloalkyl, and —C₁₋₆ alkyl, wherein each alkyl residue is optionally substituted with one to five substituents independently selected from fluorine and hydroxy and wherein phenyl, heteroaryl, and each cycloalkyl residue are optionally substituted with one to five substituents independently selected from halogen, hydroxy, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines.
 2. The compound of claim 1 wherein Ar is optionally substituted with one to three substituents independently selected from the group consisting of fluorine, chlorine, bromine, methyl, trifluoromethyl, and trifluoromethoxy.
 3. The compound of claim 2 wherein Ar is 2,5-difluorophenyl or 2,4,5-trifluorophenyl.
 4. The compound of claim 1 wherein R^(3a), R^(3b) and R^(3c) are each hydrogen.
 5. The compound of claim 1 of structural formula Ia having the indicated absolute stereochemical configuration at the two stereogenic carbon atoms marked with an *:


6. The compound of claim 1 of structural formulae Ic and Id having the indicated stereochemical configuration at the three stereogenic carbon atoms marked with an *:

wherein X, Ar, and V are as defined in claim
 1. 7. The compound of claim 6 of structural formula Ic having the indicated absolute stereochemical configuration at the three stereogenic carbon atoms marked with an *:


8. The compound of claim 7 wherein V is selected from the group consisting of:


9. The compound of claim 7 wherein V is selected from the group consisting of:


10. The compound of claim 4 wherein R² is selected from the group consisting of: hydrogen; cyano; CONH₂; C₁₋₃ alkyl, wherein alkyl is optionally substituted with one to five fluorines; and C₃₋₅ cycloalkyl, wherein cycloalkyl is optionally substituted with one to three substituents independently selected from halogen, hydroxy, and C₁₋₄ alkyl, wherein alkyl is optionally substituted with one to five fluorines.
 11. The compound of claim 4 wherein R⁸ is selected from the group consisting of: -hydrogen; -phenyl; -heteroaryl; —C₃₋₆ cycloalkyl; —SO₂C₁₋₃ alkyl; —CH₂SO₂C₁₋₃ alkyl; —SO₂C₃₋₆ cycloalkyl; and —C₁₋₅ alkyl; wherein each alkyl residue is optionally substituted with one to five substituents independently selected from fluorine and hydroxy and wherein phenyl, heteroaryl, and each cycloalkyl residue are optionally substituted with one to five substituents independently selected from halogen, hydroxy, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines.
 12. The compound of claim 1 wherein V is selected from the group consisting of:

wherein R² and R⁸ are as defined in claim
 1. 13. The compound of claim 12 wherein V is selected from the group consisting of:


14. The compound of claim 13 wherein R² is selected from the group consisting of: hydrogen; cyano; CONH₂; C₁₋₃ alkyl, wherein alkyl is optionally substituted with one to five fluorines; and C₃₋₅ cycloalkyl, wherein cycloalkyl is optionally substituted with one to three substituents independently selected from halogen, hydroxy, and C₁₋₄ alkyl, wherein alkyl is optionally substituted with one to five fluorines; and R⁸ is selected from the group consisting of: -hydrogen; -phenyl; -heteroaryl; —C₃₋₆ cycloalkyl; —SO₂C₁₋₃ alkyl; —CH₂SO₂C₁₋₃ alkyl; —SO₂C₃₋₆ cycloalkyl; and —C₁₋₅ alkyl; wherein each alkyl residue is optionally substituted with one to five substituents independently selected from fluorine and hydroxy and wherein phenyl, heteroaryl, and each cycloalkyl residue are optionally substituted with one to five substituents independently selected from halogen, hydroxy, C₁₋₆ alkyl, and C₁₋₆ alkoxy, wherein alkyl and alkoxy are optionally substituted with one to five fluorines.
 15. A pharmaceutical composition which comprises a compound of claim 1 and a pharmaceutically acceptable carrier. 